Patent Publication Number: US-11662842-B2

Title: Touch sensitive processing method and apparatus and touch system for receiving information from transmitter

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. patent application Ser. No. 15/154,313, filed on May 13, 2016 which claims benefits of Taiwan patent application, No. 104115209, filed on May 13, 2015 and the application Ser. No. 15/154,313 is also a continuation-in-part application of Ser. No. 14/537,082, filed on Nov. 10, 2014, which claims priorities under 35 U.S.C. 119 to U.S. provisional patent application, 61/902,137, filed on Nov. 8, 2013, U.S. provisional patent application, 61/945,397, filed on Feb. 27, 2014, U.S. provisional patent application, 61/992,340, filed on May 13, 2014, and U.S. provisional patent application, 62/055,995, filed on Sep. 26, 2014, the disclosures of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a transmitter, and more particularly, to the transmitter which is able to actively transmit an electric signal precisely representing a pressure on the transmitter. 
     2. Description of the Prior Art 
     Touch panel or touch sensitive screen is an important human machine interface in modern age. In addition to detecting approximation or touch of human body, touch panel is also used for detecting approximation or touch of stylus or tip of stylus such that user is able to precisely control a trace painted by a touching tip. 
     Stylus may actively emit electric signal via its tip. In the present application, it is called an active stylus. When the tip approximating to or touching on a touch panel, electromagnetic response of the electric signal occurs to electrodes of the touch panel. By detecting the electromagnetic response corresponding to the electric signal, the stylus approximating to or touching on the sensing electrodes could be detected. Therefore, a position of the tip relative to the touch panel could be concluded accordingly. 
     Traditional active stylus includes wired and wireless types. Wired active stylus is electrically supplied via a connection cable to the touch panel. Besides, signals such as one representing tip pressure could be transmitted to the touch panel via the connection cable. The most noticeable shortcoming of wired active stylus is inconvenience of the connection cable. However, wireless active stylus has to solve synchronization problem between the active stylus and the controller detecting the active stylus. Wired active stylus does not have such problem. 
     Moreover, a difference between active and passive stylus is that active stylus may sense pressure on itself. Since pressure sensor of active stylus could sense pressure level the tip is pressed, the controller detecting the active stylus or the host may gather the information. However, how to transmit the pressure level to the controller is another problem required to be solved in this field. For example, in case the information is transmitted wirelessly, cost and power consumption would be increased accordingly. Besides, the controller and the host needs to have wireless communication capability. Thus the system gets complicated accordingly. In another instance, the pressure level of the tip could be modulated and represented by amplitude of analogue signal. It may be easily misjudged or erroneous demodulated by environmental changes of temperature or moisture, various distance between the tip and the touch panel, and noise interference. 
     Hence, it is required to have active stylus transmitting electric signal which precisely reflects the pressure level. 
     From the above it is clear that prior art still has shortcomings. In order to solve these problems, efforts have long been made in vain, while ordinary products and methods offering no appropriate structures and methods. Thus, there is a need in the industry for a novel technique that solves these problems. 
     SUMMARY OF THE INVENTION 
     One aspect of the present invention is to provide a transmitter including a first sensor and a processing module electrically coupled to the first sensor. The processing module is configured to transmit a first electric signal during a first time period. The first electric signal represents at least one part of a digital sensing value of the first sensor. 
     One aspect of the present invention is to provide a method for controlling a transmitter, which includes a first sensor. The method includes transmitting a first electric signal during a first time period, and wherein the first electric signal represents at least one part of a digital sensing value of the first sensor. 
     One aspect of the present invention is to provide a touch sensitive processing apparatus, which electrically couples to multiple first electrodes and multiple second electrodes of a touch panel to detect the status of a first sensor of a transmitter, which approximates to or touches on the touch panel. The apparatus includes a signal-detecting module configured to detect a first electric signal received by one of the first and/or the second electrodes during a first time period, and a processing module configured to receive the first electric signal from the signal-detecting module and to determine a first digital value based on the first electric signal so as to represent at least one part of a digital sensing value of the first sensor of the transmitter. 
     One aspect of the present invention is to provide a method for detecting the status of a transmitter. The method includes detecting a first electric signal received by one of multiple first electrodes and/or multiple second electrodes of a touch panel during a first time period, and determining a first digital value based on the first electric signal so as to represent at least one part of a digital sensing value of a first sensor of the transmitter. 
     One aspect of the present invention is to provide a touch sensitive system including a transmitter, a touch panel, and a touch sensitive processing apparatus, which electrically coupled to multiple first electrodes and multiple second electrodes of the touch panel. The transmitter includes a first sensor and a transmitter processing module electrically coupled to the first sensor. The transmitter processing module is configured to transmit a first digital electric signal during a first time period. The first digital electric signal represents at least one part of a digital sensing value of the first sensor. The touch sensitive processing apparatus includes a signal-detecting module configured to detect the first electric signal received by one of the multiple first and/or second electrodes during the first time period, and a touch processing module configured to receive the first electric signal from the signal-detecting module and to determine a first digital value based on the first electric signal so as to represent at least one part of a digital sensing value of the first sensor. 
     One object of the present invention is to provide an active stylus which is able to transmit an electric signal precisely representing a pressure on the active stylus. 
     The above description is only an outline of the technical schemes of the present invention. Preferred embodiments of the present invention are provided below in conjunction with the attached drawings to enable one with ordinary skill in the art to better understand said and other objectives, features and advantages of the present invention and to make the present invention accordingly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention can be more fully understood by reading the following detailed description of the preferred embodiments, with reference made to the accompanying drawings, wherein: 
         FIG.  1    illustrates a diagram of a touch sensitive system  100  in accordance with an embodiment of the present invention; 
         FIG.  2    illustrates a diagram of a transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  3    illustrates a diagram of a transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  4 A  depicts a diagram of a transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  4 B  depicts a diagram of a transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  5    depicts a diagram of a transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  6    shows a flow chart of determining the sensing value of the tip of transmitter or active stylus performed by a touch sensitive apparatus in accordance with an embodiment of the present invention; 
         FIG.  7 A  illustrates a diagram of a transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  7 B  illustrates a diagram of a transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  7 C  illustrates a diagram of a transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  7 D  illustrates a diagram of a transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  8    shows a flow chart of determining the sensing value of the tip of transmitter performed by a touch sensitive apparatus in accordance with an embodiment of the present invention; 
         FIG.  9 A  shows a timing sequence of signal modulation for a transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  9 B  shows a timing sequence of signal modulation for a transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  9 C  shows a timing sequence of signal modulation for a transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  9 D  shows a timing sequence of signal modulation for a transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  9 E  shows a timing sequence of signal modulation for a transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  9 F  shows a timing sequence of signal modulation for a transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  9 G  shows a timing sequence of signal modulation for a transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  9 H  shows a timing sequence of signal modulation for a transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  9 I  shows a timing sequence of signal modulation for a transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  10    illustrates noise propagation path in accordance with an embodiment of the present invention; 
         FIG.  11    illustrates a structure diagram of a first capacitor  221  in accordance with an embodiment of the present invention; 
         FIG.  12    illustrates a diagram of reduced embodiment shown in  FIG.  11   ; 
         FIG.  13    is a variation of the embodiment shown in  FIG.  12   ; 
         FIG.  14    is a variation of the embodiment shown in  FIG.  13   ; 
         FIG.  15    is a variation of the embodiment shown in  FIG.  14   ; 
         FIG.  16 A  illustrates a diagram in accordance with an embodiment of the present invention; 
         FIG.  16 B  is a variation of the embodiment shown in  FIG.  16 A ; 
         FIGS.  17 A and  17 B  respectively show structural diagrams of the first capacitor and the second capacitor in accordance with the embodiments of the present invention; 
         FIG.  18    is a variation of the embodiment shown in  FIG.  11   ; 
         FIG.  19 A  illustrates a profiling diagram of the FSC structure used in the transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  19 B  illustrates an assembled profiling diagram of the structure shown in  FIG.  19 A ; 
         FIG.  19 C  illustrates another assembled profiling diagram of the structure shown in  FIG.  19 A ; 
         FIG.  19 D  illustrates a profiling diagram of the FSC structure used in the transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  19 E  illustrates a profiling diagram of the FSC structure used in the transmitter  110  in accordance with an embodiment of the present invention; 
         FIG.  20 (A) -(D) illustrate profiling diagrams of contact surface of the compressible conductor  1974  facing the dielectric film  1973 ; 
         FIG.  21    illustrates a pressure sensor according to an embodiment of the present invention; 
         FIG.  22    illustrates a pressure sensor according to an embodiment of the present invention; 
         FIGS.  23 A and  23 B  depict profiling diagrams of a switch structure in accordance with an embodiment of the present invention; 
         FIGS.  24 A and  24 B  depict profiling diagrams of a switch structure in accordance with an embodiment of the present invention; 
         FIG.  25    shows a diagram for calculating the tip position; 
         FIG.  26    shows a flow chart for calculating the inclination angle in accordance with an embodiment of the present invention; 
         FIGS.  27 ( a )-( e )  illustrate embodiments of how display interface reflecting strobe according to the inclination angle and/or pressure of the tip section; 
         FIGS.  28 ( a )-( b )  illustrates other embodiments of how display interface reflecting strobe according to the inclination angle and/or pressure of the tip section; 
         FIG.  29    illustrates a block diagram of a system for detecting beacon signal in accordance with an embodiment of the present invention; 
         FIG.  30    illustrates a block diagram of a transmitter in accordance with an embodiment of the present invention; 
         FIG.  31    shows a flow chart of a method for controlling a transmitter in accordance with an embodiment of the present invention; 
         FIG.  32    illustrates a block diagram of a touch processing apparatus in accordance with an embodiment of the present invention; 
         FIG.  33    shows a flow chart of a method for detecting the status of a transmitter in accordance with an embodiment of the present invention; 
         FIG.  34 A  shows a flow chart of a touch sensitive system processing interference in accordance with an embodiment of the present invention; 
         FIG.  34 B  shows a flow chart of a touch sensitive system processing interference in accordance with an embodiment of the present invention; 
         FIG.  34 C  shows a flow chart of a touch sensitive system processing interference in accordance with an embodiment of the present invention; 
         FIG.  34 D  shows a flow chart of a touch sensitive system processing interference in accordance with an embodiment of the present invention; 
         FIG.  35 (A) -(B) illustrate diagrams of signal strength of a transmitter in accordance with an embodiment of the present invention; and 
         FIG.  36    illustrates a diagram of partitions for a touch panel  120  in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Some embodiments of the present invention are described in details below. However, in addition to the descriptions given below, the present invention can be applicable to other embodiments, and the scope of the present invention is not limited by such, rather by the scope of the claims. Moreover, for better understanding and clarity of the description, some components in the drawings may not necessary be drawn to scale, in which some may be exaggerated relative to others, and irrelevant parts are omitted. 
     Please refer to  FIG.  1   , which illustrates a diagram of a touch sensitive system  100  in accordance with an embodiment of the present invention. The touch sensitive system  100  includes at least one transmitter  110 , a touch panel  120 , a touch sensitive processing apparatus  130 , and a host  140 . The transmitter  110 , e.g. in one embodiment of the present invention, may be an active stylus which emits electric signal. However, the implementations of the transmitter  110  are not restricted to that. The touch sensitive system  100  may include multiple transmitters  110 . The touch panel  120  is formed on a substrate. The touch panel  120  may be a touch sensitive screen. The present application does not limit implementations of the touch panel  120 . 
     In one embodiment, the touch sensitive area of the touch panel  120  includes multiple first electrodes  121  and multiple second electrodes  122 . Multiple capacitive coupling sensing points are located where the intersections of these two kinds of electrodes. The first and the second electrodes  121  and  122  are connected to the touch sensitive processing apparatus  130 , respectively. In a mutual capacitance detecting mode, the first electrodes  121  may be called as first conductive strips or driving electrodes, the second electrodes  122  may be called as second conductive strips or sensing electrodes. The touch sensitive processing apparatus  130  provides driving voltage (voltage of driving signal) to those first electrodes  121  and measures signal variation occurred to the second electrodes  122  to detect external conductive object approximating to or touching on the touch panel  120 . Ordinary people skilled in the art could understand the touch sensitive processing apparatus  130  could use self-capacitance mode or mutual-capacitance mode to detect approximating or touching event and object. No description is elaborated further. In addition to self-capacitance mode or mutual-capacitance mode, the touch sensitive processing apparatus  130  could further detect the electric signal emitted from the transmitter  110  to calculate a position of the transmitter  110  in relative to the touch panel  120 . In one embodiment, signal variations occurred to the first electrodes  121  and the second electrodes  122  are measured, respectively, to detect the electric signal and the position of the transmitter  110  in relative to the touch panel  120 . Since frequency of the electric signal emitted from the transmitter  110  is not identical or harmonic to frequency of driving signals in self-capacitance mode or mutual-capacitance mode, the touch sensitive processing apparatus  130  could distinguish the electric signals from the transmitter  110  and the driving signals during self-capacitance mode or mutual-capacitance mode. In another embodiment, the touch panel  120  may be surface capacitance touch sensitive panel which has four electrodes attaching to four corners or four sides. The touch sensitive processing apparatus  130  detects the position of the transmitter  110  in relative to the touch panel  120  by measuring signal variations of these four electrodes. 
     A host  140  is also shown in  FIG.  1   . It could be a central processing unit, a master processor in an embedded system, or any other form of computer. In one embodiment, the touch sensitive system  110  could be a tablet computer. The host  140  could be a CPU which runs an operating system of the tablet computer. For example, the tablet computer relies on Android operating system and the host  140  is an ARM processor which runs Android operating system. The present application does not limit the format of information transmitted between the host  140  and the touch sensitive processing apparatus  130 . It only requires that the information is related to approximating or touching event occurred to the touch panel  120 . 
     Since electric signals are emitted, the transmitter  110  or active stylus needs electric power to supply the energy of electric signals. In one embodiment, power source of the transmitter  110  may be battery or a rechargeable battery. Alternatively, power source of the transmitter  110  may be capacitor, especially an ultra-capacitor or a super-capacitor, such as one of EDLC (Electrical Double Layered Capacitor), pseudo-capacitor, and hybrid capacitor. The charging time of ultra-capacitor is counted in seconds and the discharging time is counted in hours. In other words, active stylus endures long requiring short charging time. 
     In one embodiment, the touch panel  120  periodically emits a beacon signal. When the tip of the transmitter  110  or active stylus approximates to the touch panel  120 , the transmitter  110  could detect the beacon signal via the tip. In response to the detection, the transmitter  110  begins to emit the electric signal for a while to the touch panel  120 . Consequently, the transmitter  110  may stop emitting the electric signal if no beacon signal is detected. Thus the operating time of the transmitter  110  could be extended accordingly. 
     The beacon signal could be emitted via the first electrodes  121  and/or the second electrodes  122 . In one embodiment, in case driving signals are transmitted from the first electrodes for mutual capacitance detection, frequency of the driving signals is not identical or harmonic to frequency of the beacon signal. Therefore, it is possible to transmit the driving signals and the beacon signals simultaneously. In other words, mutual-capacitance detection and the electric signal detection could be performed simultaneously. Alternatively, it takes turn to transmit the driving signals and the beacon signals. Thus mutual-capacitance detection and the electric signal detection are done in time-sharing fashion. In such case, frequency of the driving signals may or may not be identical to frequency of the beacon signals. 
     In one embodiment, in order to make the transmitter  110  detecting the beacon signals further away above the touch panel  120 , the touch sensitive processing apparatus  130  commands all of the first and the second electrodes  121  and  122  of the touch panel  120  emitting the driving signals simultaneously, such that the total signal strength emitted from the touch panel  120  could be maximized. 
     Please refer to  FIG.  2   , which depicts a diagram of a transmitter  110  in accordance with an embodiment of the present invention. The transmitter  110  includes a first signal source  211 , a second signal source  212 , a first component  221  with a first impedance Z 1 , a second component  222  with a second impedance Z 2 , and a tip section  230 . A first signal emitted from the first signal source  211  transmits to the touch panel  120  via the first component  221  and the tip section  230 . Similarly, a second signal emitted from the second signal source  212  transmits to the touch panel  120  via the second component  222  and the tip section  230 . 
     In one embodiment, the first signal includes a signal with a first frequency f 1 , the second signal includes a signal with a second frequency f 2 . The first signal with frequency f 1  and the second signal with frequency f 2  may be square-wave signals, sinuous signals, or PWM (pulse width modulation) signals. In one embodiment, the first frequency f 1  is not identical or harmonic to frequency of the beacon signal and frequency of the driving signal. The second frequency f 2  does not equal to the first frequency f 1 . Furthermore, the second frequency f 2  is not identical or harmonic to frequency of the beacon signal and frequency of the driving signal. 
     These signals with two frequencies get mixed and fed into the tip section  230  via the first component  221  with the first impedance Z 1  and the second component  222  with the second impedance Z 2 , respectively. The first and second components  221  and  222  could be any combination of resistor, inductor, and capacitor (e.g. solid state capacitor). In the embodiment as shown in  FIG.  2   , the second impedance Z 2  is fixed or constant; the first impedance Z 1  is variable or adjustable corresponding to a sensing variation of a sensor. 
     In another embodiment, both the first and second impedances Z 1  and Z 2  are variable or adjustable. A ratio of these two impedances is corresponding to a sensing variation of a sensor. In one embodiment, the sensor may be a contractible and flexible tip. The first impedance Z 1  changes corresponding to the stroke or the pressure level of the flexible tip. In some examples, the first impedance Z 1  is linearly proportional to the variation of the sensing value of the sensor. In alternative examples, the first impedance Z 1  is non-linearly proportional to the variation of the sensing value of the sensor. 
     The first and second components  221  and  222  may not be the same kind of electric component. For example, the first component  221  is a resistor and the second component  222  is a capacitor, and vice versa. In another example, the first component  221  is a resistor and the second component  222  is an inductor, and vice versa. Alternatively, the first component  221  is an inductor and the second component  222  is a capacitor, and vice versa. At least one of the first impedance Z 1  and the second impedance Z 2  is variable or adjustable. For example, it may be resistor with variable resistance, capacitor with variable capacitance, or inductor with variable inductance. In case of one of the first impedance Z 1  and the second impedance Z 2  is fixed or constant; the component may be one of the following: resistor with fixed resistance, capacitor with fixed capacitance, or inductor with fixed inductance. 
     In one embodiment, the first component  221  may be a FSR, force sensing resistor, with a variable and determinable resistance corresponding to an applied force, and the second component  222  may be a resistor with fixed resistance. In alternative embodiment, the first component may be a resistor with variable resistance. Hence, while other conditions are the same, a ratio of a first strength M 1  of signal component with the first frequency f 1  and a second strength M 2  of signal component with the second frequency f 2  in the electric signals emitted from the tip section  230  is proportional to an inverse ratio of the first and the second impedances Z 1  and Z 2 . In other words, M 1 /M 2 =k (Z 2 /Z 1 ). 
     When the transmitter  110  hovers above the touch panel  120 , since the tip section  230  is not pressed or moved, the ratio between strength M 1  of signal component with the first frequency f 1  and strength M 2  of signal component with the second frequency f 2  is a constant or a predetermined value in the electric signals detected by the touch panel  120 . Or alternatively, a ratio of (M 1 −M 2 )/(M 1 +M 2 ) or another ratio of (M 2 −M 1 )/(M 1 +M 2 ) is also a constant or a predetermined value. In addition, the pressure level may be represented as M 1 /(M 1 +M 2 ) or M 2 /(M 1 +M 2 ). Except for those four ratios mentioned above, ordinary people skilled in the art could use any other ratio involving strengths M 1  and M 2 . In other words, when the detected ratio is the constant or the predetermined value, it is concluded that the sensor did not sense any variation. In one embodiment, it means that the transmitter  110  does not contact the touch panel  120 . 
     When the transmitter  110  contacts the touch panel  120 , the tip section  230  is pressed to move. The first impedance Z 1  of the first component  221  changes according to the movement or the pressure of the tip section  230  such that the ratio of M 1  and M 2  is varied accordingly from the constant or the predetermined value. The touch panel  120  could generate corresponding sensing (pressure) value according to the ratio. The fore-mentioned constant or predetermined value may not be a number but a range with a tolerable error. 
     It is noticeable that the relation between the ratio and the sensing value may not be linear. Furthermore, the sensing value may not be linearly proportional to the movement or the pressure of the sensor. The sensing value is just a value sensed by the touch panel  120 . The present application does not limit the correspondence of the sensing value. For example, the touch panel  120  could generate the sensing value according to the ratio by looking into a look-up table or by calculations. 
     Please refer to  FIG.  3   , which shows a diagram of a transmitter  110  in accordance with an embodiment of the present invention. Similar to the embodiment shown in  FIG.  2   , the transmitter  110  includes the first signal source  211 , the second signal source  212 , a first capacitor  321  with a first capacitance C 1 , a second capacitor  322  with a second capacitance C 2 , and the tip section  230 . 
     The two signal sources  211  and  212  may be a first PWM signal source PWM 1  and a second PWM signal source PWM 2 , respectively. These two signal sources  211  and  212  may emit signals with the same frequency or not. The transmitter  110  includes the second capacitor  322  with fixed second capacitance C 2  and the first capacitor  321  with a variable first capacitance C 1 , which are connected to the signal sources PWM 2   212  and PWM 1   211 , respectively. Since the first capacitance C 1  changes according to the pressure level of the tip section  230 , the embodiment shown in  FIG.  3    may include a capacitive force sensor or a FSC, force sensing capacitor. In one embodiment, the capacitive force sensor may be implemented by PCB (printed circuit board) or any other material. The structure of the FSC would be described in paragraphs below. 
     The strength ratio of these two signal sources is inversely proportional to the impedance ratio of these two capacitors  321  and  322 . When the tip section  230  of the stylus does not touch to any object, or the force sensor does not sense any force, the resistance of the first capacitor  321  remains the same. The impedance ratio of these two capacitors  321  and  322  keeps unchanged. When the transmitter  110  hovers above the touch panel  120  and the emitted electric signals are detected, the strength ratio of these two signal sources is constant or fixed. 
     However, if the tip section  230  of the transmitter  110  is touched or the force sensor does sense force, the impedance of the first capacitor  321  changes accordingly such that the impedance ratio of these two capacitors  321  and  322  also changes accordingly. When the transmitter  110  contacts the touch panel  120  and the emitted electric signals are detected, the strength ratio of these two signal sources is varied according to the force sensed by the force sensor. 
     Please refer to  FIG.  4 A , which depicts a diagram of a transmitter  110  in accordance with an embodiment of the present invention. Similar to the embodiment as shown in  FIG.  3   , the transmitter  110  includes the first signal source  211 , the second signal source  212 , the first capacitor  321  with the first capacitance C 1 , the second capacitor  322  with the second capacitance C 2 , and the tip section  230 . The transmitter  110  may include multiple sensors to detect multiple states. In one embodiment, the tip section  230  includes a force sensor for detecting the pressure level of the tip and reflecting the pressure level to the emitted electric signal. In another embodiment, the transmitter  110  may include multiple buttons, such as eraser button and barrel button. Alternatively, the transmitter  110  may further include a switch to reflect whether the tip is touched by the touch panel or anything else. Ordinary people skilled in the art could understand that the transmitter  110  may include more buttons and other forms of sensors but not limited to those mentioned. 
     In the embodiment shown in  FIG.  4 A , the first capacitor  321  connects to an eraser capacitor  441  and a barrel capacitor  442  in parallel, which are connected in series to the eraser button and the barrel button, or switch SWE and switch SWB, respectively. When the corresponding button is pressed or the corresponding switch is shorted, the capacitor  441  or  442  is connected to the first capacitor  321  in parallel, such that it changes the capacitance of the PWM 1  signal path and the impedance ratio between the PWM 1  signal path and the PWM 2  signal path is changed accordingly. Thus the strength ratio of these two signal sources is varied in consequence. 
     Since the capacitance C 1  and impedance of the first capacitor  321  is variable, in case it is connected in parallel with the eraser capacitor  441  and the barrel capacitor  442 , the impedance ratio of the connected circuit and the second capacitor  322  resides in a range. In the embodiment as shown in  FIG.  4 A , assuming the signal strength ratio of PWM 1  and PWM 2  falls into a first range in response to the variable range of the first capacitor  321 . In case the first capacitor  321  is connected with the barrel capacitor  442  in parallel, i.e., the barrel button is pressed, the signal strength ratio of PWM 1  and PWM 2  falls into a second range. In case the first capacitor  321  is connected with the eraser capacitor  441  in parallel, i.e., the eraser button is pressed, the signal strength ratio of PWM 1  and PWM 2  falls into a third range. Further, in case the first capacitor  321  is connected with the barrel capacitor  442  and the eraser capacitor  441  in parallel, i.e., the barrel button and the eraser button are pressed, the signal strength ratio of PWM 1  and PWM 2  falls into a fourth range. In the implementation, the capacitance and impedance of the barrel capacitor  442  and the eraser capacitor  441  could be adjusted such that the first, second, third, and four ranges are not overlapped. Because the ranges are not overlapped, it is able to determine which button is pressed according to which range the signal strength ratio falls into. In consequence, the pressure level of the force sensor could be concluded according to the signal strength ratio. 
     Please refer to  FIG.  4 B , which depicts a diagram of a transmitter  110  in accordance with an embodiment of the present invention. Comparing with the embodiment shown in  FIG.  4 A , the second capacitor  322  in the embodiment of  FIG.  4 B  is configured to connect with the eraser capacitor  441  and the barrel capacitor  442 , which are connected in series to the eraser button and the barrel button, or switch SWE and switch SWB, respectively. When the corresponding button is pressed or the corresponding switch is shorted, the capacitor  441  or  442  is connected to the second capacitor  322  in parallel, the impedance ratio between the PWM 1  signal path and the PWM 2  signal path is changed accordingly. Thus the strength ratio of these two signal sources is varied in consequence. 
     Since the capacitance C 1  and impedance of the first capacitor  321  is variable, in case the second capacitor  322  is connected in parallel with the eraser capacitor  441  and the barrel capacitor  442 , the impedance ratio of the connected circuit and the first capacitor  321  resides in a range. In the embodiment shown in  FIG.  4 B , assuming the signal strength ratio of PWM 1  and PWM 2  falls into a first range in response to the variable range of the first capacitor  321 . In case the second capacitor  322  is connected with the barrel capacitor  442  in parallel, i.e., the barrel button is pressed, the signal strength ratio of PWM 1  and PWM 2  falls into a fifth range. In case the second capacitor  322  is connected with the eraser capacitor  441  in parallel, i.e., the eraser button is pressed, the signal strength ratio of PWM 1  and PWM 2  falls into a sixth range. Further, in case the second capacitor  322  is connected with the barrel capacitor  442  and the eraser capacitor  441  in parallel, i.e., the barrel button and the eraser button are pressed, the signal strength ratio of PWM 1  and PWM 2  falls into a seventh range. 
     Utilizing the same spirit embodied in  FIG.  4 A , the capacitance and impedance of the barrel capacitor  442  and the eraser capacitor  441  in  FIG.  4 B  could be adjusted such that the first, fifth, sixth, and/or seventh ranges are not overlapped. Because the ranges are not overlapped, it is able to determine which button is pressed according to which range the signal strength falls into. In consequence, the pressure level of the force sensor could be concluded according to the signal strength ratio. 
     Please refer to  FIG.  5   , which depicts a diagram of a transmitter  110  in accordance with an embodiment of the present invention. The embodiment shown in  FIG.  5    may be variation of embodiments shown in  FIGS.  2 ,  3 ,  4 A, and  4 B . Reversely, the variation of the embodiment shown in  FIG.  5    apply to the embodiments shown in  FIGS.  2 ,  3 ,  4 A, and  4 B . 
     Comparing with the embodiment shown in  FIG.  2   , the embodiment shown in  FIG.  5    further includes a ring electrode  550  and a ring wire  551 . The ring wire  551  as shown in  FIG.  5    connects to a third signal source  513  via a ring capacitor  523  with a fixed capacitance Cr. The tip section  230  is surrounded by the ring electrode  550  which is electrically coupled to the ring wire  551  and the printed circuit board in the back-end. Although it is called “ring” electrode  550  in the present application, the ring electrode  550  may include multiple electrodes in some embodiments. The present invention does not limit the number of the ring electrode  550 . For convenience, they are collectively called ring electrode  550 . The ring electrode  550  is electrically insulated to the tip section. They are not electrically coupled with each other. 
     Six switches Sw 1  through Sw 6  are shown in  FIG.  5   . The tip section  230  radiates signals from the first signal source  211  if the switch Sw 1  is shorted and the switch Sw 2  is opened. Otherwise, it could be done if the switch Sw 1  is opened or in case the switches Sw 1  and Sw 2  are shorted at the same time. Similarly, the tip section  230  radiates signals from the second signal source  212  if the switch Sw 3  is shorted and the switch Sw 4  is opened. Otherwise, it could be done if the switch Sw 3  is opened or in case the switches Sw 3  and Sw 4  are shorted simultaneously. The ring electrode  550  radiates signals from the third signal source  513  if the switch Sw 5  is shorted and switch Sw 6  is opened. Otherwise, it could be done if the switch Sw 5  is opened or in case the switches Sw 5  and Sw 6  are shorted concurrently. 
     The first signal source  211  and the second signal source  212  may emit signals with different frequencies or signals with different frequency groups. Analogously, the third signal source  513  shown in  FIG.  5    may emit signals with frequency or frequency group different to those from the first signal source  211  and the second signal source  212 . Similarly, the first signal source  211  and the second signal source  212  may transmit PWM signals. The frequency of signals transmitted from these two signal sources  211  and  212  may be identical or not. Comparably, the third signal source  513  shown in  FIG.  5    may transmit PWM signals. The frequency of signals transmitted from these three signal sources  211 ,  212  and  513  may be identical or not. 
     Please refer to  FIG.  6   , which shows a flow chart of a method for determining the sensing value of the tip of transmitter or active stylus performed by a processing apparatus in accordance with an embodiment of the present invention. The method could be executed by the touch sensitive processing apparatus  130  as shown in  FIG.  1   . The touch sensitive processing apparatus  130  connects multiple first electrodes  121  and second electrodes  122  of the touch panel  120  for detecting the electric signals emitted by the tip section  230  of the transmitter  110 . The touch sensitive processing apparatus  130  is able to determine a position the transmitter  100  in relative to the touch panel  120  according to signal strengths received by individual first electrode  121  and second electrode  122 . In addition, the method shown in  FIG.  6    could be used to determine the force sensing value of the transmitter  110 . In one instance, the force sensing value is the pressure level of the tip section  230 . 
     The embodiment shown in  FIG.  6    may be corresponding to the embodiments shown in  FIG.  2    through  FIG.  5   . The first two steps  610  and  620  calculate signal strength M 1  and M 2  of the first signal source  211  and the second signal source  212 , respectively. These two steps  610  and  620  could be done simultaneously or in any order. In case the signal from the first signal source  211  with first frequency f 1  and the signal from the second signal source  212  with second frequency f 2 , the signal strength M 1  is the strength of signal with first frequency f 1  and the signal strength M 2  is the strength of signal with second frequency f 2 . In case the signal from the first signal source  211  with first frequency group F 1  and the signal from the second signal source  212  with second frequency group F 2 , the signal strength M 1  is sum of strength of signals with each frequency in first frequency group F 1  and the signal strength M 2  is sum of strength of signals with each frequency in second frequency group F 2 . As mentioned above, the frequency in this embodiment could be PWM frequency. 
     Then in step  630 , calculating a ratio according to M 1  and M 2 . Five examples of the ratio are already enumerated above, such as M 1 /M 2 , (M 1 −M 2 )/(M 1 +M 2 ), (M 2 −M 1 )/(M 1 +M 2 ), M 1 /(M 1 +M 2 ), and M 2 /(M 1 +M 2 ). Ordinary people skilled in the art could use any other ratio involving M 1  and M 2  in addition to those examples. Next, step  640  is performed for determining whether the ratio is a predetermined value or falls into a predetermined range. If the result is true, the flow goes to step  650 . It is determined that the transmitter  110  is hovering above the touch panel  120 . Otherwise, the flow executes step  660  for calculating a sensing value of the tip section  230  according to the ratio. The sensing value may or may not be relevant to the pressure level or moving distance of the tip section  230 . The calculations of the sensing value could be done by looking into a lookup table, linear interpolation, and/or quadratic curve interpolation. It depends on the relation between the ratio and the sensing value. 
     When the method shown in  FIG.  6    applies to the embodiments shown in  FIGS.  4 A and  4 B , additional steps could be performed in step  660 . For example, when it applies to the embodiment shown in  FIG.  4 A , the flow may further determine which one of the first, second, third, and fourth ranges the ratio calculated in step  630  falls into. Hence, it is able to determine whether the barrel button and/or the eraser button are pressed or not in addition to the sensing value of the tip section  230 . Analogously, when it applies to the embodiment shown in  FIG.  4 B , the flow may further determine which one of the first, fifth, sixth, and seventh ranges the ratio calculated in step  630  falls into. Hence, it is able to determine whether the barrel button and/or the eraser button are pressed or not in addition to the sensing value of the tip section  230 . 
     In one embodiment of the present application, the controller or circuit inside the transmitter  110  does not need to determine the pressure level of the tip section  230 . It simply requires that one or both the first impedance Z 1  of the first component  221  and the second impedance Z 2  of the second component  222  change according to the pressure level of the tip section  230  such that one of the signal strength of first frequency f 1  or first frequency group F 1  and the signal strength of second frequency f 2  or second frequency group F 2  change in consequence. Therefore, the pressure level of the tip section  230  could be calculated according to a ratio between the strength M 1  of signals with first frequency f 1  or first frequency group F 1  and the strength M 2  of signals with second frequency f 2  or second frequency F 2  is demodulated from the electric signals received by the touch panel  120 . 
     Please refer to  FIG.  7 A , which illustrates a diagram of a transmitter  110  in accordance with an embodiment of the present invention. Comparing with embodiments shown in  FIG.  2    through  FIG.  5   , the transmitter  110  shown in  FIG.  7 A  also includes a first component  221  with a first impedance Z 1 , a second component  222  with a second impedance Z 2 , and a tip section  230 . The first component  221  and the second component  222  may be any or any combination of resistor, inductor, and capacitor. In the embodiment as shown in  FIG.  7 A , the second impedance Z 2  may be fixed and the first impedance Z 1  is variable or adjustable corresponding to a variation of a sensor, such as pressure level of the tip section  230 . The first component  221  and the second component  222  as shown in  FIG.  7 A  could adopt those components with same numerals shown in  FIG.  2    through  FIG.  5   . No duplicated description is elaborated here. 
     Comparing with the previous embodiments, the difference resides in the embodiment shown in  FIG.  7 A  is including a single signal source  714  which is configured to transmit electric signals to the first component  221  and the second component  222  and a controller  760  which is configured to measure a first current value I 1  and a second current value I 2  outputted from the first component  221  and the second component  222 , respectively. The controller  760  is further configured to calculated a ratio which may be one of the followings: I 1 /(I 1 +I 2 ), I 2 /(I 1 +I 2 ), I 1 /I 2 , I 2 /I 1 , (I 1 −I 2 )/(I 1 +I 2 ), (I 2 −I 1 )/(I 1 +I 2 ) and etc. Ordinary people skilled in the art can calculated any other ratio involving the current values I 1  and I 2 . 
     The calculated ratio could be used to conclude the pressure level of the tip section  230 . The controller  760  can transmit information derived from the calculation of the first current value I 1  and the second current value I 2  through a transmitter wireless communication unit  770 . The host  140  may receive the information via a host wireless communication unit  780  to get the pressure level of the tip section  230 . 
     Please refer to  FIG.  7 B , which illustrates a diagram of a transmitter  110  in accordance with an embodiment of the present invention. The difference to the embodiment shown in  FIG.  7 A  resides that the controller  760  may transmit information derived from the calculation of the first current value I 1  and the second current value I 2  via a transmitter wired communication unit  771 . The host  140  may receive the information via a host wired communication unit  781  to get the pressure level of the tip section  230 . 
     Please refer to  FIG.  7 C , which illustrates a diagram of a transmitter  110  in accordance with an embodiment of the present invention. The difference to the embodiment shown in  FIG.  7 B  resides that the transmitter  110  no longer has the single signal source  714 . Instead, the transmitter  110  uses the electric signal from the transmitter wired communication unit  771  as the signal source. Since the transmitter wired communication unit  771  is connected to the host wired communication unit  781 , the electric signal is supplied by the power of the host  140 . 
     Please refer to  FIG.  7 D , which illustrates a diagram of a transmitter  110  in accordance with an embodiment of the present invention. The difference to the embodiment shown in  FIG.  7 A  resides that the transmitter  110  no longer has the single signal source  714 . Instead, the transmitter  110  uses received signal from the first electrodes  121  and/or the second electrodes  122  of the touch panel  120  as the signal source when the tip section  230  approximates to or touches on the touch panel  120 . 
     It is worthy mentioned that the embodiments shown in  FIGS.  7 A through  7 D  could use the variation shown in  FIG.  3   . The first component  221  may be the fore-mentioned first capacitor  321 . The second component  222  may be the fore-mentioned second capacitor  322 . Similarly, the embodiments shown in  FIGS.  7 A through  7 D  could use the variations shown in  FIGS.  4 A and  4 B . The first component  221  may be connected with component corresponding to other switch in parallel, or the second component  222  may be connected with components corresponding to other switch in parallel, such that the controller  760  could conclude the state of the switch according to which range where the calculated ratio falls into. 
     Please refer to  FIG.  8   , which shows a flow chart of a method for determining a sensing value of the tip section of the transmitter performed by a touch sensitive processing apparatus in accordance with an embodiment of the present invention. The embodiment shown in  FIG.  8    is quite similar to the embodiment shown in  FIG.  6   , which is configured to calculate the sensing value according to a ratio between a signal strength M 1  of a first frequency (group) and a signal strength M 2  of a second frequency (group). The embodiment shown in  FIG.  8    is configured to apply to implementation with a single signal source, which is configured to calculate the ratio between a first current value I 1  through the first component  221  and a second current value I 2  through the second component  222 . 
     The method may be executed by the controller  760  of the embodiments shown in  FIGS.  7 A through  7 D . The first two steps  810  and  820  are configured for calculating a first current value I 1  through the first component  221  and a second current value I 2  through the second component  222 , respectively. These two steps  810  and  820  may be performed simultaneously, or in any order. Next, in step  830 , calculating a ratio of I 1  and I 2 . Several examples of the ratio are already enumerated above, such as I 1 /(I 1 +I 2 ), I 2 /(I 1 +I 2 ), I 1 /I 2 , I 2 /I 1 , (I 1 −I 2 )/(I 1 +I 2 ), (I 2 −I 1 )/(I 1 +I 2 ), and etc. Next, in step  840 , determining whether the ratio is a predetermined value or falls into a predetermined range. If the result is true, the flow goes to step  850 , it is determined that the transmitter is hovering above the touch panel  120 . Otherwise, the flow goes to step  860 , calculating a sensing value of the tip section  230  according to the ratio. The sensing value may or may not be relevant to the pressure level or moving distance of the tip section  230 . The calculations of the sensing value could be done by looking into a lookup table, linear interpolation, and/or quadratic curve interpolation. It depends on the relation between the ratio and the sensing value. 
     When the method shown in  FIG.  8    applies to the embodiments shown in  FIGS.  4 A and  4 B , additional steps could be performed in step  860 . For example, when it applies to the embodiment shown in  FIG.  4 A , the flow may further determine which one of the first, second, third, and fourth ranges the ratio calculated in step  830  falls into. Hence, it is able to determine whether the barrel button and/or the eraser button are pressed or not in addition to the sensing value of the tip section  230 . Analogously, when it applies to the embodiment shown in  FIG.  4 B , the flow may further determine which one of the first, fifth, sixth, and seventh ranges the ratio calculated in step  830  falls into. Hence, it is able to determine whether the barrel button and/or the eraser button are pressed or not in addition to the sensing value of the tip section  230 . 
     Please refer to  FIG.  9 A , which shows a timing sequence of signal modulation of the transmitter  110  in accordance with an embodiment of the present invention. The embodiment shown in  FIG.  9 A  may apply to the transmitter  110  as shown in  FIG.  2    through  FIG.  5   . The horizontal axis of  FIG.  9 A  is a time axis by order from left to right. As shown in  FIG.  9 A , an optional noise detection period is included prior to a beacon signal is emitted by the touch panel/screen  120 . The noise detected during the period may come from the touch panel/screen, the electronic system thereof, and/or background environment. The touch panel/screen  120  and the touch sensitive processing apparatus  130  may detect one or more frequencies of noise signals. Noise detection would be described later. 
     In one embodiment, the touch panel/screen  120  transmits beacon signals. The transmitter  110  includes a demodulator for detecting the beacon signal. Please refer to  FIG.  29   , which illustrates a block diagram of a system for detecting beacon signal in accordance with an embodiment of the present invention. The system  2900  includes a receiving electrode  2910 , a detecting module  2920 , and a demodulator  2930 . In one embodiment, the receiving electrode  2910  may be the ring electrode  550 , the tip section  230 , or any other electrodes. The receiving electrode  2910  forwards the received signal to the detecting module  2920 . 
     The detecting module  2920  includes an analogous front end  2921  and a comparator  2922 . Ordinary people skilled in the art could understand what the analogous front end  2921  does which is not elaborated here. In this embodiment, the analogous  2921  outputs a voltage signal representing the signal strength. The comparator  2922  is configured to compare a reference voltage Vref and a voltage signal representing the signal strength. If the voltage signal is higher than the reference voltage, it means that the received signal is strong enough. Thus, the comparator  2922  outputs an activation signal or an enable signal to the demodulator  2930  which is configured to demodulate the received signal to determine whether the received signal contains the frequency of the beacon signal. If the voltage signal is lower than the reference voltage, the comparator  2922  may output a disable signal to the demodulator  2930 . Consequently, the demodulator  2930  stops demodulating the received signal. 
     When the transmitter  110  did not receive the beacon signal for a while, it could be switched to a sleep mode for shutting the demodulator  2930  down to reduce power consumption. However, since the power consumption of the detecting module  2920  is not significant, the detecting module  2920  could continue detecting whether the signal strength of the received signal is over a predetermined value in the sleep mode. Once the signal strength of the received signal is more than the predetermined value, the transmitter  110  may switch from the sleep mode to an energy saving mode which consumes more power for activating the demodulator  2930 . In the same time, the rest parts of the transmitter  110  may still rest in the power down state. If the demodulator  2930  determines that the received signal does not contain the beacon signal, the demodulator  2930  may be shut down after some time and the transmitter  110  switches from the energy saving mode back to the sleep mode which consume less power. Instead, if the demodulator  2930  determines that the received signal does contain the beacon signal, the demodulator  2930  can wake up the rest parts of the transmitter  110  such that the transmitter switches from the energy saving mode to normal working mode. 
     Now, back to embodiment of  FIG.  9 A , after a delay period enduring L 0  length, the transmitter  110  emits electric signal during T 0  and T 1  periods. There may exist a delay period enduring L 1  length between the T 0  and T 1  periods. The length of T 0  period may or may not equal to the length of T 1  period. The T 0  and T 1  periods are collectively called a signal frame. The touch sensitive processing apparatus  130  detects the electric signals emitted from the transmitter  110  during T 0  and T 1  periods. Next, after another optional delay time enduring L 2  length, the touch sensitive processing apparatus  130  may perform optional other detection, e.g., fore-mentioned capacitance detection mode for detecting passive stylus or finger. 
     The present invention does not limit the lengths of delay times L 0 , L 1 , and L 2 , which may be zero or any other duration. The lengths of delay times L 0 , L 1 , and L 2  may or may not be relevant. In one embodiment, among those periods shown in  FIG.  9 A , only the T 0  and T 1  periods of the signal frame are mandatory, other periods are optional. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                   
                 Barrel 
                 Eraser 
                   
               
               
                   
                   
                   
                 button 
                 button 
                   
               
               
                 State 
                 Signal Source 
                 Period 
                 pressed 
                 pressed 
                 Other state 
               
               
                   
               
             
            
               
                 Hovering 
                 1 st  signal  
                 T0 
                 F0 
                 F1 
                 F0 
               
               
                   
                 source 
                 T1 
                 F1 
                 F2 
                 F2 
               
               
                   
                 2 nd  signal  
                 T0 
                 F0 
                 F1 
                 F0 
               
               
                   
                 source 
                 T1 
                 F1 
                 F2 
                 F2 
               
               
                   
               
            
           
         
       
     
     Please refer to Table 1, which shows a modulation table of electric signals emitted by the transmitter  110  in accordance with an embodiment of the present invention. As shown in Table 1, the state of the transmitter  110  is hovering, i.e., no pressure is measured by the force sensor. Since the tip section  230  of the transmitter  110  does not contact the touch panel/screen  120 , the first and second signal sources  211  and  212  emit the same frequency group Fx simultaneously in the same period in order to enhance the signal strength in the embodiment shown in Table 1. For example, in case the barrel button is pressed, these two signal sources both emits frequency group F 0  during the T 0  period and frequency F 1  during the T 1  period. If the touch sensitive processing apparatus  130  detects signals with frequency group F 0  during the T 0  period and signals with frequency group F 1  during the T 1  period, it determines that the barrel button of the hovering transmitter  110  is pressed. 
     The frequency group Fx includes at least one frequency. Frequencies classified in the same frequency group are interchangeable. For example, frequency group F 0  includes f 0  and f 3  frequencies; frequency group F 1  includes f 1  and f 4  frequencies; and frequency group F 2  includes f 2  and f 5  frequencies. No matter which one of f 0  and f 3  frequencies is detected, the touch sensitive processing apparatus  130  takes that frequency group F 0  is received. 
     In another embodiment, it is not required to have both signal sources  211  and  212  of the transmitter  110  emitting signals with the same frequency group. Table 1 is just an example of the present embodiment. Besides, the transmitter  110  may include more buttons or sensors. The present invention does not limit to two buttons. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                   
                   
                   
                 Barrel 
                 Eraser 
                   
               
               
                   
                   
                   
                 button 
                 button 
                   
               
               
                 State 
                 Signal Source 
                 Period 
                 pressed 
                 pressed 
                 Other state 
               
               
                   
               
             
            
               
                 Touching 
                 2 nd  signal  
                 T0 
                 F0 
                 F1 
                 F0 
               
               
                   
                 source 
                 T1 
                 GND 
                 GND 
                 GND 
               
               
                   
                 1 st  signal  
                 T0 
                 GND 
                 GND 
                 GND 
               
               
                   
                 source 
                 T1 
                 F1 
                 F2 
                 F2 
               
               
                   
               
            
           
         
       
     
     Please refer to Table 2, which shows a modulation table of electric signals emitted by the transmitter  110  in accordance with an embodiment of the present invention. As shown in Table 2, the state of the tip section  230  of the transmitter  110  is touching, i.e., pressure is measured by the force sensor. 
     With regard to the embodiment shown in  FIG.  4 A , the following describes what happened if the barrel button SWB is pressed. During the T 0  period, the output of the first signal source  211  is grounded and the second signal source  212  emits signals with frequency group F 0 . Hence, the electric signals of the transmitter  110  during the T 0  period only have the frequency group F 0  emitted from the second signal source  212 . During the T 1  period, the output of the second signal source  212  is grounded and the first signal source  211  emits signals with frequency group F 1 . Furthermore, since the impedance of the first capacitor  321  is changed in the touching state, the pressure level of the tip section  230  could be calculated according to the ratio of the signal strengths with regard to the received frequency groups F 0  and F 1  during the T 0  and T 1  periods, respectively. Besides, because the touch sensitive processing apparatus  130  detects frequency group F 0  during the T 0  period and detects frequency group F 1  during the T 1  period, it determines that the barrel button is pressed. 
     With regard to the embodiment shown in  FIG.  4 B , the following describes what happened if the barrel button SWB is pressed. During the T 0  period, the output of the first signal source  211  is grounded and the second signal source  212  emits signals with frequency group F 0 . The second capacitor  322  is connected with the barrel capacitor  442  in parallel. Although the electric signals emitted from the transmitter  110  during the T 0  period only contains signals with frequency group F 0  from the second signal source  212 , the signal strength is different from the one which the barrel button is not pressed. During the T 1  period, the output of the second signal source  212  is grounded and the first signal source  211  emits signals with frequency group F 1 . Furthermore, since the impedance of the first capacitor  321  is changed in the touching state, the pressure level of the tip section  230  could be calculated according to the ratio of the signal strengths with regard to the received frequency groups F 0  and F 1  during the T 0  and T 1  periods, respectively. Besides, because the touch sensitive processing apparatus  130  detects frequency group F 0  during the T 0  period and detects frequency group F 1  during the T 1  period, it determines that the barrel button is pressed. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                   
                   
                   
                 Barrel 
                 Eraser 
                   
               
               
                   
                   
                   
                 button 
                 button 
                   
               
               
                 State 
                 Signal Source 
                 Period 
                 pressed 
                 pressed 
                 Other state 
               
               
                   
               
             
            
               
                 Hovering 
                 2 nd  signal  
                 T0 
                 F0 
                 F1 
                 F2 
               
               
                   
                 source 
                 T1 
                 F0 
                 F1 
                 F2 
               
               
                   
                 1 st  signal  
                 T0 
                 F0 
                 F1 
                 F2 
               
               
                   
                 source 
                 T1 
                 F0 
                 F1 
                 F2 
               
               
                   
               
            
           
         
       
     
     Please refer to Table 3, which shows a modulation table of electric signals emitted by the transmitter  110  in accordance with an embodiment of the present invention. In this embodiment, according to the received frequency group, it is able to know which button is pressed. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 4 
               
               
                   
               
               
                   
                   
                   
                 Barrel 
                 Eraser 
                   
               
               
                   
                   
                   
                 button 
                 button 
                   
               
               
                 State 
                 Signal Source 
                 Period 
                 pressed 
                 pressed 
                 Other state 
               
               
                   
               
             
            
               
                 Touching 
                 2 nd  signal  
                 T0 
                 F0 
                 F1 
                 F2 
               
               
                   
                 source 
                 T1 
                 GND 
                 GND 
                 GND 
               
               
                   
                 1 st  signal  
                 T0 
                 GND 
                 GND 
                 GND 
               
               
                   
                 source 
                 T1 
                 F0 
                 F1 
                 F2 
               
               
                   
               
            
           
         
       
     
     Please refer to Table 4, which shows a modulation table of electric signals emitted by the transmitter  110  in accordance with an embodiment of the present invention. In this embodiment, according to the received frequency group, it is able to know which button is pressed. The pressure level of the tip section could be calculated according to a ratio of received signal strength between the T 0  and T 1  periods. 
     Please refer to  FIG.  9 B , which shows a timing sequence of signal modulation of the transmitter  110  in accordance with an embodiment of the present invention. The embodiment is a variation of the embodiment shown in  FIG.  9 A . The difference between these two embodiments shown in  FIGS.  9 A and  9 B  is a noise detection taking place after the T 1  period. After that, other detection is performed. 
     Please refer to  FIG.  9 C , which shows a timing sequence of signal modulation of the transmitter  110  in accordance with an embodiment of the present invention. The modulation shown in  FIG.  9 C  may apply to the transmitter  110  shown in  FIG.  5   . One additional function of the ring electrode  550  is to enhance the signal strength of active stylus in hovering state. Thus the detection range of the hovering active stylus could be increased consequently. 
     The modulation shown in  FIG.  9 C  is when the transmitter  110  is hovering. In this state, the time period which the transmitter  110  emits signals contains the R time period, merely. During this R period, both the ring electrode  550  and the tip section  230  transmit electric signals together. In one embodiment, the electric signals may come from the same signal source with the same frequency and/or modulation. For example, both the ring electrode  550  and the tip section  230  transmit signals from the third signal source  513 . In another instance, both the ring electrode  550  and the tip section  230  may simultaneously transmit signals from the first, the second, and the third signal sources in turns, such that the maximum power for each signal sources can be utilized. The touch sensitive processing apparatus  130  can conclude the position the transmitter  110  is hovering above the touch panel  120  by detecting the electric signals emitted from the ring electrode  550  during the R period. If the electric signals from the ring electrode  550  and the tip section  230  comes from the same signal source or have the same frequency group, the signal strength would be maximized. In consequence, the range of the hovering transmitter  110  detected by the touch panel  120  would be maximized. Alternatively, the transmitter  110  transmits electric signals via only the ring electrode  550  during the R period. 
     Please refer to  FIG.  9 D , which shows a timing sequence of signal modulation of the transmitter  110  in accordance with an embodiment of the present invention. The modulation shown in  FIG.  9 D  may apply to the transmitter  110  shown in  FIG.  5   . In the embodiment shown in  FIG.  9 C , a delay time or blank period L 1  is included after the R period. The touch panel  120  performs other detection after the L 1  period. Comparing with the embodiment shown in  FIG.  9 C , the L 1  period in the embodiment shown in  FIG.  9 D  is extended. Comparing with the embodiment shown in  FIG.  9 E , the L 1  period in the embodiment shown in  FIG.  9 D  equals to the sum of L 1 , T 0 , L 2 , T 1 , and T 3  periods. Thus, if no further electric signal could be detected by the touch sensitive processing apparatus  130  shown in  FIG.  9 D , it is determined that the transmitter  110  is in the state of hovering. 
     Please refer to  FIG.  9 E , which shows a timing sequence of signal modulation of the transmitter  110  in accordance with an embodiment of the present invention. The modulation shown in  FIG.  9 E  may apply to the transmitter  110  shown in  FIG.  5   . The embodiment shown in  FIG.  9 E  is equivalent to add an R period prior to the time frame of the embodiment shown in  FIG.  9 A . In this embodiment, no matter whether the tip section  230  is touched or not, the transmitter  110  always transmits electric signal from the tip section  230  during the T 0  and T 1  periods such that some logic design for controlling could be omitted. However, comparing with the embodiments shown in  FIGS.  9 C and  9 D , the embodiment shown in  FIG.  9 E  would waste power consumption during the T 0  and T 1  periods. On the other hand, the touch sensitive processing apparatus  130  no longer needs to perform detection during the R period as long as the electric signals from the tip section  230  could be detected during the T 0  and T 1  periods. It could be determined that whether the tip section  230  is pressed or not and further determined that the transmitter  110  is in the state of hovering or not. 
     Please refer to  FIG.  9 F , which shows a timing sequence of signal modulation of the transmitter  110  in accordance with an embodiment of the present invention. The modulation shown in  FIG.  9 F  may apply to the transmitter  110  shown in  FIG.  5   . In the embodiment shown in  FIG.  9 E , no proportional relation is defined over lengths of the R, T 0 , and T 1  periods. Instead, in the embodiment shown in  FIG.  9 F , the ratios between lengths of the R, T 0 , and T 1  periods is 1:2:4. Assuming that the touch sensitive processing apparatus  130  could perform N sampling during one time unit, where N is a positive integer. Hence, the touch sensitive processing apparatus  130  could perform N, 2N, and 4N samplings during the R, T 0 , and T 1  periods, respectively. The present invention does not limit the ratios among the lengths of these three periods. In one instance, the period with the most powerful electric signal endures the shortest time; the period with the weakest electric signal endures the longest time. For examples, the ratios may be 1:3:2, 1:2:3, or etc. The design of ratios depends on the implementation. Although the paragraphs above enumerate modulations in two periods T 0  and T 1  merely, the present invention does not limit to that. More periods are applicable to the present invention. 
     In those  FIGS.  9 A- 9 F  mentioned above, the pressure value sensed by the tip section  230  can be calculated based on the strength ratios of different signals received in different periods. In some embodiments of the present invention, the transmitter  110  does not need to sense the pressure value on the tip section  230  and it can make the electric signal transmitted from the tip section  230  reflect the pressure value. 
     In other embodiments, the transmitter  110  could include an apparatus for measuring the pressure value on the tip section  230 , and this could be implemented through those mentioned in  FIG.  6    or  FIG.  8   . Or, it could be fulfilled by a manometer, the parts of capacitor, resistor, and inductor for measuring pressure, and analog-to-digital converters (ADCs). The present invention does not limit to the used apparatus, and the requirement is that the transmitter  110  can measure and acquire a digital representing value or pressure digital value of the pressure the tip section  230  being pressed. 
     According to the requirement of design accuracy, the pressure digital value mentioned above could have several accuracy degrees. For example, 10 accuracy degrees or resolutions, in a sample case, could be included but thousands of accuracy degrees or resolutions could be applied in a complex case. The present invention does not limit to the accuracy or resolution of the pressure digital value. In one embodiment, the pressure digital value may include 256 accuracy degrees; the pressure digital value, in another embodiment, may include 16 accuracy degrees; and still another embodiment, the press digital value may include 1024 accuracy degrees. 
     The accuracy degree mentioned above may be represented in many manners, such as decimal system. Assumed the pressure digital value has 256 accuracy degrees, 3 decimal digitals may be used to denote it or 2 hexadecimal digitals may be used to represent it as well or even 8 binary digitals may be applied to denote it. Assumed the pressure digital value has 512 accuracy degrees, 3 decimal digitals may be used to denote it or 3 hexadecimal digitals may be used to represent it as well. The present invention does not limit to the representing manner of the pressure digital value. 
     One of the features of the present invention is that the transmitter  110  adopts at least one or multiple periods to send out electric signals representing pressure values. It is noted that the electric signals sent here don&#39;t need to be traditional square wave signals. They can also be sine wave signals or other types of signals. The present invention is not limited if the electric signals have any coded or modulated forms. It is only required the touch sensitive processing apparatus  130  can detect whether the transmitter  110  sends electric signals or not. In short, the touch sensitive processing apparatus  130  only determines whether the transmitter  110  sends out electric signals or not instead of its coded or modulated forms of electric signals. And further, when the touch sensitive processing apparatus  130  determines that the transmitter  110  sends out electric signals, the starting time and the time length of the sent electric signals can be decided. 
     In one embodiment, as shown in  FIG.  9 A , the transmitter  110  adopts two periods T 0  and T 1  to send out electric signals representing pressure values. Assumed the pressure digital value includes 256 accuracy degrees, two hexadecimal digitals can be used to represent it, and these two digitals can be represented by the electric signals of the periods T 0  and T 1 , respectively. The electric signals of period T 0  can represent a higher digital, and the electric signals of period T 1  can represent a lower digital. In other words, this invention doesn&#39;t restrict to the digital orders of each period. Namely, it can be Big Endian or Little Endian. 
     Assumed the period T 0  is used to denote the hexadecimal digital, the form of the sent and unsent electric signals can be used to represent a hexadecimal digital. In one embodiment, the period T 0  can be divided into 15 sub-periods. When the transmitter  110  sends electric signals in each sub-period, 15 is the represented number. When the transmitter  110  doesn&#39;t send electric signals in the 15 sub-periods, 0 is the represented number. Among the 15 sub-periods, 7 sub-periods show the sent electric signals, 7 is the represented number. For example, 001111111000000 represents 7; 101010101010100 also stands for 7; 000000001111111 also means 7. Among the 15 sub-periods, 12 sub-periods show the sent electric signals, 12 is the represented number. In this embodiment, the present invention is not limited if the sub-periods of the sent electric signals are continuous or separated. Also, the positions or the orders of the sub-periods are not restricted. As long as the number of the sent electric signals of the sub-periods can be counted when the touch sensitive processing apparatus  130  is receiving electric signals, one digital of the pressure value can be explained. 
     In some embodiments, each period of the present invention isn&#39;t necessarily provided with the same length. For example, when three decimal numbers are used to represent the pressure digital value 256, the period of the hundred digital only needs three sub-periods, the three possibilities 0, 1, 2 can be represented. When decimal numbers are used to stand for the pressure digital value 512, the period of the hundred digital is divided into 5 sub-periods, the three possibilities 0˜5 can be shown. In this case, the sub-period to represent the hundred digital is then shorter than the other two periods. 
     In some embodiments, one period of the hexadecimal numbers represented can be divided into more than 15 sub-periods in order to add redundancy code, error detecting and/or correcting code, check code, etc. Moreover, one period of the decimal numbers represented can be divided into more than 9 sub-periods in order to add fault-tolerant code, error detecting and/or correcting code, check code, etc. In one embodiment, the code type of asynchronous transmission is adopted in each period. In short, the present invention is not limited to the signal types of modulation and demodulation. 
     In this application, concerning the related description of the previous  FIG.  9 A  to  FIG.  9 F , except for the differences of the modulated types of the electric signals, the rest can be used to send out the pressure value by the digital signals in the embodiments. For instance, the delayed time of the above-mentioned periods L 1 , L 2 , L 3  can be 0 or any length. 
     As shown in  FIG.  9 D , when the tip section  230  doesn&#39;t touch any object, that is, the transmitter  110  is in hovering state, the transmitter  110  doesn&#39;t send out any signal in L 1  period. The touch sensitive processing apparatus  130  through R period detected by the transmitter detects the transmitter  110  sending signals in hovering state. A shown in  FIG.  9    E, when the tip section  230  touches the touch panel  120 , the touch sensitive processing apparatus  130  in  FIG.  9 E  detects the pressure digital value sent by the transmitter  110  in corresponding of L 1 , T 0 , L 2 , T 1 , L 3  periods of L 1  period in  FIG.  9 A . Although only the periods T 0  and T 1  are shown in the embodiment of  FIG.  9 A  to  FIG.  9 F , this application can be applied to at least one period&#39;s or more than three periods&#39; emitting periods for the pressure digital values. 
     In this application, when the transmitter  110  sends out the digital signals of the pressure digital value represented through multiple periods, the transmitter  110  can adopt different modulated forms among these periods. For instance, the above-mentioned pressure digital values 256 or 512, in which their represented hundred digital&#39;s period and other two periods have different modulated ways and time. In another embodiment, the represented hundred digital&#39;s period and other two periods can have the same modulated time but by different ways of modulation. 
     Although in the above-mentioned embodiment of this application, the pressure values of tip section  230  serve as the sending target of the electric signals, this application is not limited to this. The present invention can send any receiving digital values of many possibly stated sensors from the transmitter  110  through this way. For instance, when the transmitter  110  has two buttons, these two buttons can include four statuses. Accordingly, the transmitter  110  can send 0˜3 electric signals in one period to represent the detecting situations of these buttons. In another embodiment, when the transmitter  110  is equipped with three buttons, these three buttons can include eight statuses. As a result, the transmitter  110  can send 0˜7 electric signals in one period to show the detecting situations of these buttons. In one embodiment, the period to send these button statuses can be the above-mentioned R period detected by the transmitter. When the digital values of button statuses are sent in R period, the touch sensitive processing apparatus  130  can simultaneously detect the hovering state of the transmitter  110 , which notably shows the button states of the transmitter  110 . 
     In one embodiment, the digital values transmitted in R period can be sent out through the tip section  230 , and it can also be sent out through the ring electrode  550 . Also, they can be simultaneously sent out through both the tip section  230  and the ring electrode  550  in order for the detection of the touch sensitive processing apparatus  130 . Please refer to the descriptions of the embodiments in  FIG.  25    and  FIG.  26   . 
     In one embodiment, the above-mentioned electric signals can consist of one signal frequency group or signals with only one signal frequency. Therefore, the touch sensitive processing apparatus  130  can lock the frequency group or single frequency by filters or demodulators to detect if the transmitter  110  sends out the electronic signals or not. In  FIG.  9 A  to  FIG.  9 F , the transmitter  110  and/or the touch sensitive processing apparatus  130  can implement the noise detection. When the transmitter  110  and/or the touch sensitive processing apparatus  130  detect(s) that the frequency of noise is the same as the frequency of the electric signals, the transmitter  110  can use another frequency group or another frequency to transmit electric signals. This part refers to the following related illustration. 
     The touch sensitive processing apparatus  130  can adopt many ways to detect the transmitter  110 . In one embodiment, filters, integrators and comparators can be used to deal with the receiving signals from the first electrodes  121  and the second electrodes  122 . The filters are used to filter noise of other frequencies, the integrators are applied to sample the signals, and the comparators are used to compare the sampling results to see if they are over the default value. The default value can be the interior noise value of the touch sensitive processing apparatus  130  or the frequently-receiving noise value of the touch panel  120 . When the sampling results are over the default value, that is, the receiving signals are larger than noise value, it means the sampling result is the electric signals detected and it shows 1 otherwise 0. Similarly, the filtering procedure, integrating procedure and comparing procedure can be used to cope with the receiving signals of the first electrodes  121  and the second electrodes  122  to judge if the sampling result is the detected electric signals. 
     In one embodiment, the integrator adopted can be dual slope integrator, whose integrating procedure used can be the method of dual slope integration. In one embodiment, the above-mentioned default value can be 0 or the comparators or the comparing procedure can be omitted. 
     In some embodiments, the touch sensitive processing apparatus  130  can use a demodulator to handle the signals received by the first and the second electrodes  121  and  122 . The demodulator has multiple embodying ways. To put it simply, the demodulator can multiply the sampling signals and intended receiving frequency signals together and then add them up. When the total number is larger than one certain default value, it means the sampling result is the electric signals detected and it shows 1 otherwise 0. 
     In the above-mentioned embodiments, each period to represent pressure digital value has its fixed length, so through the time that the transmitter sends out the electronic signals, it can use the ratio of occupying the period to show certain value of the pressure digital value. In another embodiment of the present invention, the unfixed length of the transmitting period of the electronic signals can be adapted to represent one certain value of the pressure digital value. When the transmission of the electronic signals was interrupted, it represents that the transmitting time of the digital value is over and the next transmission of the electronic signal represents next digital value. 
     Referring to  FIG.  9 G , it shows a timing sequence of signal modulation for a transmitter  110  in accordance with an embodiment of the present invention. The signal modulation in  FIG.  9 G  could apply to the transmitter  110  shown in  FIG.  5   . The embodiment in  FIG.  9 G  can adopt the length of the transmitting time of the two electric signals D 0  and D 1 , which respectively show the two values of the digital pressure value. As shown in  FIG.  9 G , the length of the transmitting time of the electric signal D 0  is 4 units, while the length of the transmitting time of the electric signal D 1  is 8 units. If the decimal system is used to represent the numbers, the pressure values can be explained as  48 . 
     In this embodiment, period R is optional. When the transmitter  110  has to send out the electric signals in R period to offer the touch sensitive processing apparatus  130  to detect its location, and R period is used to represent sensing states of other sensors, the digital values of sensing states of these sensors cannot be coded from 0, or not including 0. That is, the electronic signals cannot but be transmitted. For instance, when the transmitter  110  intends to send out digital state values of two buttons, in one embodiment, the four digital state values can be 1, 2, 3, and 4. In another embodiment, the values can be 2, 3, 4, and 5. In still another embodiment, the values can be 2, 4, 6, and 8. In yet another embodiment, the values can be 1, 3, 5, and 7. The transmitter  110  sends out several units of time length of the electric signals based on the above-mentioned digital state values. 
     Similarly, when the transmitting periods of the electric signals D 0  and D 1  are used to represent the digital values, the modulated form of none-zero length can be adopted as well. For example, a decimal value can stand for 1˜10 or 2˜11 instead of 0˜9. A hexadecimal value can stand for 1˜16 or 2˜17 instead of 0˜15. For instance, when the transmitter  110  sends out the pressure digital values representing 8, the electric signal (D 0  period) of one timing length can be sent out first and after the electric signals are interrupted, the electric signals (D 1  period) of nine timing lengths can then be sent out. 
     As shown in  FIG.  9 G , the period of pausing transmitting electric signals between D 0  and D 1  is called L 2 . The length of L 2  period can be a default value, such as the timing length of two units. The present invention is not limited to the timing length of transmitting electric signals of pause among each period. These timing lengths of pause can be the same and can also be different. 
     Referring to  FIG.  9 H , it shows a timing sequence of signal modulation for a transmitter  110  in accordance with an embodiment of the present invention. The signal modulation in  FIG.  9 H  can apply to the transmitter  110  shown in  FIG.  5   . In this embodiment, the periods R, D 0 , D 1 , and D 2  used for the transmitter  110  to transmit electric signals are unfixed length. Based on the timing length of the detected electric signals, the touch sensitive processing apparatus  130  determines the digital sensing values of each sensor on the transmitter  110 . As mentioned above, the transmitter  110  sends out electric signals in periods R, D 0 , D 1 , and D 2 . This invention is not limited to the modulated forms of electric signals. 
     In the embodiments shown in  FIG.  9 G  and  FIG.  9 H , the transmitter  110  represents certain value based on the timing length of continuous electric signals sent in one period. This value can be used to represent certain digital in number system based on certain number, which represents digital sensing values of certain sensor on the transmitter  110 . 
     As shown in  FIG.  9 I , it shows a timing sequence of signal modulation for a transmitter  110  in accordance with an embodiment of the present invention. The signal modulation in  FIG.  9 I  can apply to the transmitter  110  shown in  FIG.  5   . In this embodiment, three fixed timing lengths, the periods F 0 , F 1 , and F 2 , are used respectively to represent three digitals in number system based on certain number. As shown in  FIG.  9 I , these three periods can have the same timing lengths and they can have different ones as well. 
     In this embodiment, the transmitter  110  uses certain frequent signal to represent certain digital in number system based on certain number, which represents digital sensing values of certain sensor on the transmitter  110 . In one embodiment, the frequency of the signal can be PRF (Pulse Repetition Frequency). For instance, certain PRFx is used as a base, standing for 0. The multiple PRFxN stands for N−1. In addition, the fraction 1/PRFxN stands for N−1. Moreover, the method of looking lookup instead of the multiple can be used to represent certain digital in number system based on certain number. The present invention is not limited to the relation between the two PRFs representing the two values. Since PRF is the number of pulse within one period, whether periods F 0 , F 1 , and F 2  are long or short, as long as the sampling rate of the touch sensitive processing apparatus  130  is high enough, the PRF of signals within these periods can be estimated. 
     Similarly, the transmitter  110  can use the same way through modulating PRF in period R to modulate the sensing values of other sensors to enable the touch sensitive processing apparatus  130  to acquire the sensing values of other sensors through PRF of period R. The timing length of period R can have the same length to other periods, or it can be different as well. 
     In one embodiment, the transmitter  110  could transmit stronger electric signals in the state of hovering and transmit weaker electric signals in the state of touching. Consequently, it increases the chance for the touch sensitive processing apparatus  130  detects the transmitter  110  hovering above the touch panel  120 . When the transmitter  110  contacts the touch panel  120 , it further reduces the power consumption of the transmitter  110 . 
     For examples, in the embodiments shown in  FIGS.  9 C and  9 D , when the tip section  230  is not touched, the electric signal emitted during the R period is stronger than the electric signal emitted during the L 1  period which corresponding to the T 0  and T 1  periods. For instance, during the R period, the electric signals transmitted from the tip section  230  and the ring electrode  550  are from the first signal source  211 , the second signal source  212 , and the third signal source  513 . Therefore, the electric signals transmitted out in the R period are the sum of the outputs of these three signal sources  211 ,  212 , and  513 . 
     In the Table 1 embodiment shown in  FIG.  9 A , when the transmitter  110  is in the state of hovering, output powers come from the first signal source  211  and the second signal source  212 . In the Table 2, when the transmitter  110  is in the state of touching, output powers come from one of the first signal source  211  and the second signal source  212  during the T 0  and T 1  periods. Hence, the transmitter  110  emits stronger electric signal if the tip section is not touched and emits weaker electric signal if the tip section is pressed. 
     Similarly, in the Table 3, the transmitter  110  utilizes output powers from both the first signal source  211  and the second signal source  212  in the state of hovering. Instead, in the Table 4, the transmitter  110  in the state of touching makes use of one of the first signal source  211  and the second signal source  212  during the T 0  and T 1  periods. Hence, the transmitter  110  emits stronger electric signal if the tip section is not touched and emits weaker electric signal if the tip section is pressed. 
     The reason for adding noise detection process and period in the embodiments shown in  FIGS.  9 A through  9 I  is described below. Please refer to  FIG.  10   , which shows noise propagation path in accordance with an embodiment of the present invention. As shown in  FIG.  10   , the electronics  100  including the touch panel  120  emits noise signals with frequency f 0 , which is a member of frequency group F 0 . It is assumed that the frequency group F 0  contains another member frequency f 3 . When user holds the electronics  100 , the noise with frequency f 0  would propagate to the touch panel  120  via the user&#39;s finger. If no noise detection is performed, the touch panel  120  may take the noise with frequency f 0  from the finger as the electric signal emitted by the transmitter  110 . Hence, if the noise with frequency f 0  could be detected in advanced, it could be filtered out from the signal frame. 
     In case the transmitter  110  is capable to change frequency, it can automatically transmit signal with another member frequency f 3  of the frequency group F 0  if the noise with frequency f 0  emitted from the touch panel  120  is detected. Consequently, during the periods of signal frame, the touch sensitive processing apparatus  130  detects signal with frequency f 3  from the transmitter  110  and noise signal with frequency f 0  from the finger. This confuses the touch sensitive processing apparatus  130 . Therefore, it can perform a noise detection after the T 1  period or the signal frame as the embodiment shown in  FIG.  9 B . At this moment, since the transmitter  110  ceases transmitting signals with frequency f 3  while the noise signal with frequency f 0  from the finger and the touch panel  120  stands still, it could be determined by the touch sensitive processing apparatus  130  that the signal with frequency f 3  detected during the time frame is the signal come from the transmitter  110 . 
     In one embodiment of this invention, the transmitter  110  receives beacon signals from the touch panel  120  and sends out electric signals to the touch panel  120 . On the other hand, the touch panel  120  receives the electric signals from the transmitter  110  and sends out the beacon signals to the transmitter  110 . The transmitter  110  and the touch panel  120  can be viewed as two transceivers of the wireless communications, which can both transmit and receive signals. Among the wireless communications, receiving interfering signals or receiving no signal is two situations that need to be taken into consideration when the transceivers receive signals. 
     In one embodiment, when the transmitter  110  is so far away from the touch panel  120  so that the transmitter  110  couldn&#39;t receive the beacon signal from the touch panel  120 , the transmitter  110  then stops sending out electric signals. On the other hand, after the touch sensitive processing apparatus  130  sends out beacon signals, if the electric signals from the transmitter  110  are not detected, the power-saving mode will be launched to pause transmitting the beacon signals or reducing sending out the frequency of the beacon signals. 
     The above-mentioned beacon signals can have many varieties of frequencies and specific modulated ways, such as the modulated ways of ASK, QPSK or BPSK, etc. According to the specifically frequency and modulated ways, the transmitter  110  can determine if it is interfered by the noise. For example, if the signals demodulated by the transmitter  110  include not only the signals defined in advance but also other signals, the beacon signals can be regarded as being interfered. In other examples, if the demodulated signals only include one part of the previously-defined signals without other parts included, the beacon signals can also be regarded as being interfered. Since the interfered aspect of the received signals from the judgement of the receiver has been a well-known skill to those skilled in the art, the examples will not be listed here. The present invention is not limited to how the transmitter  110  determines the interfered ways of the beacon signals. Likewise, the present invention lists many modulated types of the electric signals. Similarly, the present invention is not limited to how the touch sensitive processing apparatus  130  determines the interfered ways of the electric signals. 
     In one embodiment, when the transceivers determine the signals, which are going to be received, being interfered, another frequency will be automatically switched to receive signals. 
     Referring to  FIG.  34 A , it shows a flow chart of a touch sensitive system processing interference in accordance with an embodiment of the present invention. Assumed the beacon signals can be one of the two frequencies, these two frequencies are respectively named frequency A and frequency B. As the step  3402 , the touch sensitive processing apparatus  130  sends out the beacon signals with frequency A. Later on, as the step  3404 , when the transmitter  110  intends to receive the beacon signals with frequency A and finds interference, the transmitter  110  doesn&#39;t send out the electric signals but receive the beacon signals with frequency B instead. In the optional step  3406 , the touch sensitive processing apparatus  130  sends out the beacon signals with frequency A one time or many times without receiving any electric signals, and then in step  3408 , the touch sensitive processing apparatus  130  changes to send out the beacon signals with frequency B. By doing so, the transmitter  110  can successfully receive the beacon signals with frequency B and then sends out the electric signals in step  3410 . 
     Since the touch sensitive processing apparatus  130  cannot receive the electric signals sent by the transmitter  110 , which means the beacon signals sent out by itself are under interference, it then switches the beacon signal frequency. Another possible reason is because the transmitter  110  has not been in the area of receiving beacon signals, the touch sensitive processing apparatus  130  can pause sending out beacon signals or prolong the interval among sending out beacon signals to reduce power consumption after all the possible frequencies are switched. 
     Similarly, referring to  FIG.  34 B , it shows a flow chart of a touch sensitive system processing interference in accordance with an embodiment of the present invention. Assumed the beacon signals can be one of the three frequencies, these three frequencies are respectively named frequency A, frequency B, and frequency J. Frequencies A and B are normal frequencies of the beacon signals, and frequency J is a specially cautious frequency, representing the electric signals received by the touch sensitive processing apparatus  130  being interfered. The electric signals can be one of the three frequencies, respectively called frequency X, frequency Y, and frequency Z. 
     In step  3412 , the touch sensitive processing apparatus  130  sends out the beacon signals with frequency A. Later on, in step  3414 , the transmitter  110  successfully receives the beacon signals with frequency A and sends out the electric signals with frequency X. When the touch sensitive processing apparatus  130  determines the electric signals with frequency X being interfered in step  3416 , the touch sensitive processing apparatus  130 , in step  3418 , sends out the beacon signals with frequency J to show interference of the electric signals with frequency X. When the transmitter  110  cannot receive the beacon signals with frequency A, in step  3422  it switches to receive the beacon signals with frequency B. In step  3422 , the touch sensitive processing apparatus  130  continuously sends out the beacon signals with frequency J to represent the inference of the electric signals with frequency X. When the transmitter  110  cannot receive the beacon signals with frequency B, in step  3424  it switches to receive the beacon signals with frequency J. In step  3426 , when the beacon signals with frequency J sent out by the touch sensitive processing apparatus  130  are successfully received by the transmitter  110 , the transmitter  110  then in step  3428  switches the electric signals&#39; transmitting frequencies from frequency X to frequency Y and in step  3430  sends out the electric signals with frequency Y. 
     In one embodiment, as shown in  FIG.  34    B, in step  3432 , the transmitter  110  makes the frequencies of the beacon signals for receiving switch from frequency J to original frequency A. Since the electric signals with frequency Y are not interfered, the touch sensitive processing apparatus  130  doesn&#39;t send out the beacon signals with frequency J. On the other hand, in step  3434 , it switches to send out the original beacon signals with frequency A. The transmitter  110  successfully receives the beacon signals with frequency A and sends out the electric signals with new frequency J in step  3436 . The touch sensitive processing apparatus  130  successfully uses the beacon signals with frequency J to inform the transmitter  110  to switch frequencies of the electric signals. 
     In one embodiment, the transmitter  110 , not necessarily mentioned as in step  3432 , switches the frequencies of the beacon signals for receiving from frequency J to original frequency A. Instead, it continues to detect beacon signals with frequency J. However, since the touch sensitive processing apparatus  130  doesn&#39;t send out the beacon signals with frequency J, the transmitter  110  cannot receive them and then switches to the power-saving mode. When the transmitter  110  restarts, it will restore to the state of receiving the beacon signals with frequency A. 
     In one embodiment, assumed the electric signals with frequency Y are still interfered, the touch sensitive processing apparatus  130  sends out the beacon signals with frequency J similarly. When the transmitter  110  receives the beacon signals with frequency J again through the mechanism of receiving beacon signal frequencies that are switched automatically, the frequencies of the electric signals are switched from frequency Y to frequency Z. 
     In short, when the touch sensitive processing apparatus  130  determines the electric signals of the received frequencies being interfered, it can inform the transmitter  110  to switch the frequencies of the electric signals through sending out the beacon signals with one specific frequency or one specifically modulated form. 
     In one embodiment, the transceivers can actively scan the interfered channels and then choose the frequencies of the transmitting and receiving signals based on the order that the two sides of communication know. 
     Referring to  FIG.  34 C , it shows a flow chart of a touch sensitive system processing interference in accordance with an embodiment of the present invention. In this embodiment, the possible frequencies of the beacon signals include frequency A, and frequency B, and the frequencies of the electric signals include frequency X, frequency Y, and frequency Z. Therefore, these two signals include six combinations. Assumed the order is AX, AY, AZ, BX, BY, and BZ, the transmitter  110  and the touch sensitive processing apparatus  130  perform the steps of scanning interference in step  3440  and  3442 , respectively. For example, the possible interfering frequencies of the beacon signals are first scanned and the possible interfering frequencies of the electric signals are scanned later, that is, the orders of frequencies A, B, X, Y, and Z are scanned one after one. In this embodiment, assumed the transmitter  110  and the touch sensitive processing apparatus  130  respectively find frequency A and frequency X have interfered signals or noises, based on the above-mentioned orders, these four combinations of these two interfered frequencies are deleted. Namely, there are only two combinations, BY and BZ, left. Since the order of BY is earlier than BZ, the two sides have chosen the combination BY respectively in step  3440  and in step  3442 . In other words, when the touch sensitive processing apparatus  130  is scheduled to send out the beacon signals with frequency B and is ready to receive the electric signals with frequency Y. And, the transmitter  110  prepares to receive the beacon signals with frequency B and prepares to send out the electric signal with frequency Y. Accordingly, the touch sensitive processing apparatus  130  sends out the beacon signals with frequency B in step  3444  and the transmitter  110  sends out the electric signals with frequency Y in step  3446  immediately. 
     In some cases, for example, the interference source from different distances to both sides may cause the transmitter  110  and the touch sensitive processing apparatus  130  to get not always the same interfering frequency after actively scanning. For instance, the transmitter  110  only scans the interfering signals of frequency A and the touch sensitive processing apparatus  130  only scans the interfering signals of frequency X. In these situations, the first combination the transmitter  110  get may be BX and the first combination the touch sensitive processing apparatus  130  get may be AY. In spite of this, the mechanism that the two sides still depend on the receiving frequencies of the above-mentioned automatic switching and on sending out beacon signals with frequency J makes the final communication frequencies be able to adjust to the combination BY. 
     In one embodiment, the purpose to accelerate the above-mentioned process is to make the transceivers detect the interfered frequencies first and then transmit the noise of the interfered frequencies to make the other side detect. Referring to  FIG.  34 D , it shows a flow chart of a touch sensitive system processing interference in accordance with an embodiment of the present invention. The difference from the embodiment of  FIG.  34 C  is that the transmitter  110  scans the interfered signals of frequency A in step  3450 , so it sends out noise of frequency A in step  3456  to let the touch sensitive processing apparatus  130  detect. On the contrary, the touch sensitive processing apparatus  130  in step  3452  scans the interfered signals of frequency X. Accordingly, in step  3454  it sends out noise of frequency X to let the transmitter  110  detect. By doing so, after the detecting steps finish, the two sides all scan that there are interfered signals or noise from frequency A and frequency X. Therefore, as the embodiment shown in  FIG.  34 C , the two sides coincidentally or independently choose BY combination and repeat the step  3444  and the step  3446 . 
     Although the only two scanning steps  3450  and  3452  are described in  FIG.  34 D , in real situation, the active scanning may not just scan all frequencies one time, it can scan two or even more times lest it miss the signals of the interfered frequencies deliberately transmitted form the other side. 
     Besides, although in the embodiment shown in  FIG.  34 D  the two scanning steps  3450  and  3452  start and finish at the same time, they can start and finish at different time. The periods that the two scanning steps take are not always the same and the times of the scanning frequency can be different. In spite of the fact that in some situations the other side may miss the signals of transmitted interfered frequencies, in most cases the combinations of the more interfered frequencies can be deleted to make both sides adjust more quickly to undisturbed frequency in order to proceed communication. 
     In the embodiments of  FIG.  34 C  and  FIG.  34 D , both sides have the ability of actively scanning. Especially in the embodiment of  FIG.  34 D , both sides have the ability to actively send out signals of the interfered frequencies. However, in this invention the ability of both sides is not limited to be equal. In one embodiment, the transmitter  110  can have the abilities to actively scan and actively send out signals of the interfered frequencies. On the other hand, the touch sensitive processing apparatus  130  can only have the ability of actively scanning. In this embodiment, although the touch sensitive processing apparatus  130  lacks the ability to actively send out signals of the interfered frequencies, compared with the embodiment in  FIG.  34 C , these two sides have more chances to even more quickly find out the frequencies that are undisturbed for both sides to proceed communication. On the contrary, in another embodiment, the touch sensitive processing apparatus  130  have the abilities to actively scan and actively send out signals of the interfered frequencies and the transmitter  110  only have the ability of actively scanning. But, compared with the embodiment in  FIG.  34 C , the two sides have more chances to even more quickly find out the undisturbed frequencies for both sides to communicate. 
     Similarly, when one of the two sides doesn&#39;t have the ability to actively scan and the other has the ability to scan actively, compared with the embodiments in  FIG.  34 A  and  FIG.  34 B , it can have more chances to even more quickly find out the undisturbed frequencies for both sides to proceed communication. 
     It is mentioned in the description related to  FIG.  2    that the signal strength ratio is changed according to impedance variation of the first component  221 . Please refer to  FIG.  11   , which depicts a structure diagram of a first capacitor  221  in accordance with an embodiment of the present invention. By changing the impedance of the first capacitor  221  to adjust the signal strength ratio of multiple frequencies. Traditional capacitor is formed by two plates of conducting metal. The capacitance C is proportional to the permittivity and the plate areas and inversely proportional to the distance between these two plates. 
     One aspect of the embodiment is to use a mechanic structure for transforming a displacement along the axis of the transmitter  110  to another displacement vertical or angled to the axis. By creating the displacement, the capacitance and first impedance Z 1  of the first capacitor  221  are changed accordingly while keeps the capacitance and second impedance Z 2  of the second capacitor  222  intact, such that the ratio between the signal strength M 1  with first frequency (group) and the signal strength M 2  with second frequency (group). 
     There exist three non-contacting metal plates shown in  FIG.  11   . The first capacitor  221  is formed by a first metal plate  1110  and a second metal plate  1120 . The second capacitor  222  is formed by the second metal plate  1120  and a third metal plate  1130 . In one instance, the first metal plate  1110  is formed on a flexible circuit board or printed circuit board which covers with insulating paint or dielectric plate. The second metal plate  1120  and the third metal plate  1130  are formed in the double sides of the same circuit board or printed circuit board which also covers with insulating paint or dielectric plate. The second metal plate  1120  is coupled to the fore-end tip section  230  through wiring. The tip is attached to a lifting element  1140  (e.g. the ramp means). A movement of the tip can directly or indirectly deform whole or part of the first metal plate  1110  (and flexible circuit board or PCB) such that a displacement vertical to along the axis of the transmitter  110  or stylus is created accordingly. 
     The first metal plate  1110  is supplied with electric signal with first frequency (group) and the third metal plate  1130  is supplied with electric signal with second frequency (group). Therefore current induced in the second metal plate  1120  generates signals with the first frequency (group) and the second frequency (group) which is sent to the touch panel  120  via the fore-end tip section  230 . When the tip section  230  is not pressed, the first metal plate  1110  and its circuit board do not have a displacement vertical to the axis of the transmitter  110 . However, when the tip section  230  is pressed, the ramp means  1140  transforms the force parallel to the axis to the direction vertical to the axis such that the circuit board of the first metal plate  1110  deforms and moves. Furthermore, the permittivity of the first capacitor  221  changes accordingly, so do the capacitance C 1  and impedance Z 1  of the first capacitor  221 . When the tip section  230  is pressed, the circuit board of the second metal plate  1120  and the third metal plate  1130  moves as a whole. Therefore the capacitance C 2  and impedance Z 2  of the second capacitor  222  remains the same. 
     Since the circuit board of the first metal plate  1110  deforms upward, the embodiment may include at least one supporting element  1150  to provide support downward for helping the circuit board of the first metal plate  1110  recover to the original shape after the pressure to the tip section  230  is dismissed. When the circuit board is not deformed, the supporting force provided by the supporting element may be zero. 
     In one example of the present embodiment, the capacitances of the first capacitor  221  and the second capacitor  222  may be designed to be equal. If so, the permittivity, distance, and area of these two capacitors are the same. However, the present invention does not limit to the condition. It only requires that the touch sensitive processing apparatus  130  knows about the impedance ratio between these two capacitors of the transmitter  110 . 
     In this embodiment, expensive force sensing resistor is replaced by cheaper circuit board or PCB. Besides, if the capacitances of the first capacitor  221  and the second capacitor  222  are designed to be equal, permittivity of these two capacitors  221  and  222  would be varied in the same rate due to environmental change. Hence the default ratio could be maintained consequently. Besides, it does not require any active controlling component to adjust the ratio of these two impedances Z 1  and Z 2 . The transmitter  110  could provide electric signal passively. So many resources could be saved. 
     Please refer to  FIG.  12   , which shows a diagram of reduced embodiment shown in  FIG.  11   . The circuit board, supporting element  1150 , and the wiring between the second metal plate  1120  and the tip section  230  are omitted. The description of embodiment shown in  FIG.  12    can refer to those for  FIG.  11   . 
     Please refer to  FIG.  13   , which is a variation of the embodiment shown in  FIG.  12   . The third metal plate  1130  is moved to the position behind the first metal plate  1110  and they are not electrically coupled. When the tip section  230  is pressed, only the first metal plate  1110  and its circuit board deform. In some examples, the first metal plate  1110  and the third metal plate  1130  may be formed on the same circuit board. 
     Please refer to  FIG.  14   , which is a variation of the embodiment shown in  FIG.  13   . The first metal plate  1110  and the third metal plate  1130  comprise two plates A and B, respectively. They are feed into signals with first frequency (group) and second frequency (group), respectively. When the tip section  230  is pressed, the first metal plate A  1110 A, the first metal plate B  1110 B, and their circuit board deforms, but the third metal plate A  1130 A, the third metal plate B  1130 B, and their circuit board do not deform. Comparing with the embodiment shown in  FIG.  13   , since there are two deforming metal plates  1110 A and  1110 B, the impedance variation would be larger and more obvious than the variation of the embodiment shown in  FIG.  13   . 
     Please refer to  FIG.  15   , which is a variation of the embodiment shown in  FIG.  14   . The second metal plate  1120  also comprise two plate A  1120 A and plate B  1120 B, which are coupled to the tip section  230  through wiring. A first capacitor A  221 A is formed by the first metal plate A  1110 A and the second metal A  1120 A. A second capacitor A  222 A is formed by the second metal plate A  1120 A and the third metal plate A  1130 A. A first capacitor B  221 B is formed by the first metal plate B  1110 B and the second metal B  1120 B. A second capacitor B  222 B is formed by the second metal plate B  1120 B and the third metal plate B  1130 B. When the tip section is pressed, the first metal plate A  1110 A, the first metal plate B  1110 B, and their circuit boards deform. However, the third metal plate A  1130 A, the third metal plate B  1130 B, and their circuit boards remains the same. Comparing with the embodiment shown in  FIG.  13   , since there are two deforming metal plates  1110 A and  1110 B, the impedance variation would be larger and more obvious than the variation of the embodiment shown in  FIG.  13   . 
     Please refer to  FIG.  16 A , which shows a structure in accordance with an embodiment of the present invention. In the embodiment shown in  FIG.  16 A , there are a first metal plate  1110 , a second metal plate  1120 , and a third metal plate  1130  from top to bottom. The first metal plate  1110  and the third metal plate  1130  are fixed and fed in signals with first frequency (group) and second frequency (group), respectively. Current induced from the second metal plate  1120  generates electric signals mixed with first frequency (group) and second frequency (group). 
     A first capacitor  221  is formed by the first metal plate  1110  and the second metal plate  1120 . A second capacitor  222  is formed by the second metal plate  1120  and the third metal plate  1130 . When the second metal plate  1120  is not deformed, the impedances of the first capacitor  221  and the second capacitor  222  are fixed in the same environment. Hence a strength ratio of signal with first frequency (group) and signal with second frequency (group) contained in the electric signal could be calculated. If the ratio is a predetermined value or falls into a predetermined range, it is concluded that the second metal plate  1120  is not deformed. 
     If the second metal plate  1120  deforms, the impedances and capacitances of the first capacitor  221  and the second capacitor  222  change accordingly. In consequence, a strength ratio could be calculated according to these two signal strength values. Based on the variation of the ratio, the deforming and displacement of the second metal plate  1120  could be calculated. Steps shown in the embodiment of  FIG.  6    could be applicable here. 
     Please refer to  FIG.  16 B , which is a variation of the embodiment shown in  FIG.  16 A . The second metal plate  1120  and the third metal plate  1130  are fixed and fed in signals with first frequency (group) and second frequency (group), respectively. Current induced from the first metal plate  1110  generates electric signals mixed with first frequency (group) and second frequency (group). 
     A first capacitor  221  is formed by the first metal plate  1110  and the second metal plate  1120 . A second capacitor  222  is formed by the first metal plate  1110  and the third metal plate  1130 . When the first metal plate  1110  is not deformed, the impedances of the first capacitor  221  and the second capacitor  222  are fixed in the same environment. Hence a strength ratio of signal with first frequency (group) and signal with second frequency (group) contained in the electric signal could be calculated. If the ratio is a predetermined value or falls into a predetermined range, it is concluded that the first metal plate  1110  is not deformed. 
     If the first metal plate  1110  deforms, the impedances and capacitances of the first capacitor  221  and the second capacitor  222  change accordingly. In consequence, a strength ratio could be calculated according to these two signal strength values. Based on the variation of the ratio, the deforming and displacement of the first metal plate  1110  could be calculated. Steps shown in the embodiment of FIG.  6  could be applicable here. The impedance may be changed according to variations of temperature and humanity. However, both impedances of the first capacitor  221  and the second capacitor  222  change together according to the environmental variations of temperature and humanity. Therefore, influence on the ratio caused by temperature and humanity could be reduced or eliminated. 
     Please refer to  FIGS.  17 A and  17 B , which show structural diagrams of the first capacitor and the second capacitor in accordance with an embodiment of the present invention. In the embodiment shown in  FIGS.  16 A and  16 B , signals with first frequency (group) and second frequency (group) are fed. However, in the embodiment shown in  FIGS.  17 A and  17 B , a driving signal with the same frequency is fed. In other words, the embodiments can be applicable to those embodiments shown in  FIGS.  7 A through  7 D . The driving signal fed in could be the signal source  714  of the embodiments shown in  FIGS.  7 A and  7 B . The electric signal from the transmitter wired communication unit  771  of the embodiment shown in  FIG.  7 C  could be the signal source. Moreover, the electric signal received from the first electrodes  121  and/or the second electrodes  122  of the touch panel  120  when the tip section  230  shown in  FIG.  7 D  approximates or touches could be used as the signal source. 
     The structure of three metal plates as shown in  FIG.  17 A  is identical to the structure of three metal plates as shown in  FIG.  16 A . A driving signal with a frequency may feed into the deformable second metal plate  1120 . Due to capacitive effect with the second metal plate  1120 , the first metal plate  1110  outputs the induced current with a current value I 1 . Analogously, due to capacitive effect with the second metal plate  1120 , the third metal plate  1130  outputs the induced current with a current value I 2 . 
     A first capacitor  221  is formed by the first metal plate  1110  and the second metal plate  1120 . A second capacitor  222  is formed by the second metal plate  1120  and the third metal plate  1130 . When the second metal plate  1120  is not deformed, the impedances of the first capacitor  221  and the second capacitor  222  are fixed. Hence, the current values I 1  and I 2  are analyzed and a ratio is calculated according to these two current values. When the ratio is a predetermined value or falls into a predetermined range, it is determined that the second metal plate  1120  is not deformed. 
     When the second metal plate  1120  is deformed, the impedances and capacitance of the first capacitor  221  and the second capacitor  222  are changed. Hence, a ratio is calculated according to these two current values. Based on the variation of the ratio, the deforming and displacement of the second metal plate  1120  could be deduced in consequence. The method embodiment shown in  FIG.  8    could be applicable here. 
     Please refer to  FIG.  17 B , which is a variation of the embodiment shown in  FIG.  17 A . The second metal plate  1120  and the third metal plate  1130  are fixed. The driving signal with a frequency is fed into the deformable first metal plate  1110 . Due to capacitive effect with the first metal plate  1110 , the second metal plate  1120  outputs the induced current with a current value I 1 . Analogously, due to capacitive effect with the first metal plate  1110 , the third metal plate  1130  outputs the induced current with a current value I 2 . 
     A first capacitor  221  is formed by the first metal plate  1110  and the second metal plate  1120 . A second capacitor  222  is formed by the first metal plate  1110  and the third metal plate  1130 . When the first metal plate  1110  is not deformed, the impedances of the first capacitor  221  and the second capacitor  222  are fixed. Hence, the current values I 1  and I 2  are analyzed and a ratio is calculated according to these two current values. When the ratio is a predetermined value or falls into a predetermined range, it is determined that the first metal plate  1110  is not deformed. 
     When the first metal plate  1110  is deformed, the impedances and capacitance of the first capacitor  221  and the second capacitor  222  are changed. Hence, a ratio is calculated according to these two current values. Based on the variation of the ratio, the deforming and displacement of the first metal plate  1110  could be deduced in consequence. The method embodiment shown in  FIG.  8    could be applicable here. 
     Please refer to  FIG.  18   , which is a variation of the embodiment shown in  FIG.  11   . The embodiment shown in  FIG.  11    requires feeding signals with two different frequencies. Instead, in the embodiment shown in  FIG.  18    as well as those shown in  FIGS.  17 A and  17 B , it is required to feed driving signal with a frequency or some kind of signal, merely. No matter how many frequencies contained in the signal fed in. 
     A first capacitor  221  is formed by the first metal plate  1110  and the second metal plate  1120 . A second capacitor  222  is formed by the second metal plate  1120  and the third metal plate  1130 . Since the distance and permittivity between the second metal plate  1120  and the third metal plate  1130  are not changed, the capacitance and impedance of the second capacitor  222  is fixed. When the first metal plate  1110  is not deformed, the impedances of the first capacitor  221  and the second capacitor  222  are fixed. Hence, a ratio of analyzed current value I 1  and I 2  could be calculated. When the ratio is a predetermined value or falls into a predetermined range, it is determined that the first metal plate  1110  is not deformed. Moreover, the deforming of the first metal plate  1110  changes its own capacitance and impedance. Thus when it is deformed due to external force, the current value I 1  is changed accordingly. In consequence, the ratio involving the current values I 1  and I 2  also changes. Based on the variation of the ratio, the deforming and displacement of the first metal plate  1110  could be deduced in consequence. The method embodiment shown in  FIG.  8    could be applicable here. 
     In alternative embodiment of the present invention, the controller or circuit of the transmitter  110  may feed driving signal with a frequency into the second metal plate  1120  and calculate the current values I 1  and I 2  through the first capacitor  221  and the second capacitor  222 , respectively. By using the ratio of these two current values, a sensing value of pressure level of the tip section is deduced accordingly. In other words, utilizing the mechanism including the first impedance Z 1  and the second impedance Z 2 , the present invention provides a design of FSC, force sensing capacitor, which may replace traditional force sensing components, such as FSR (force sensing resistor), for detecting pressure level. The FSC provided by the present invention has characteristics such as low cost and immune to influence of temperature and humanity. As shown in the figures above, FSC utilizing flexible PCB is disclosed by present invention. One aspect of the present application is to provide novel forms of FSC. 
     Please refer to  FIG.  19 A , which depicts a profiling diagram of the FSC structure used in the transmitter  110  in accordance with an embodiment of the present invention. Please be noted that scales of  FIGS.  19 A through  19 E  are changed to highlight some important parts. Besides, some fixed components are omitted for simplifying the figure. As shown in  FIG.  19 A , the most left component is a long rod tip or the tip section  230 , which is a conductor. For convenience, the tip section  230  is at the fore end of the transmitter  110  or active stylus. When the tip section  230  contacts the fore moving part  1971 , the tip section  230  is electrically coupled to the fore moving part  1971 . The fore moving part  1971  could be joined together with a rear moving part  1972  by protruding fasteners in the middle of the fore moving part  1971  and corresponding recessed fasteners in the middle of the rear moving part  1972 . In one embodiment, the protruding and recessed fasteners comprise screw thread or whorl. Both the fore and rear moving parts  1971  and  1972  may be conductors or conductive elements, such as metal. 
     A shell component  1980 , shown in  FIG.  19 A , circularly embraces the fore and rear moving parts  1971  and  1972 . Only parts of the shell component  1980  are illustrated in  FIG.  19 A . A neck part with smaller diameter of the shell component  1980  is constructed nearby the tip section  230 . A shoulder part with larger diameter next to the neck part of the shell component is used to be a bearing part. As shown in  FIG.  19 A , at least one elastic element  1978  is placed between the bearing part and the fore moving part  1971 . The elastic element  1978 , such as spring, elastic piece, or in any other forms, is supposed to provide force between the shell component  1980  and the fore moving part  1971  along the axis of the stylus. In some embodiments, the elastic element  1978  unlike the one shown in  FIG.  19 A  is surrounded the moving part  1970  and the neck part of the shell component  1980 . 
     In another embodiment, the elastic element  1978  may provide force to both the shell component  1980  and the rear moving part  1972  along the axis of the stylus. Because a whole moving part  1970  composed of the fore and the rear moving parts  1971  and  1972  by fasteners, no matter which one of the fore and the rear moving part  1971  and  1972  is pressed, the whole moving part  1970  is pushed to the tip and the tip section  230  is also pushed forward accordingly. 
     In case the tip section  230  is pressed toward the right hand side of  FIG.  19 A  or toward the rear, the force provided by the elastic element  1978  is compromised and the elastic element  1978  would be compressed such that a portion of the moving part  1970  touches the bearing part of the shell component  1980 . Hence, the design provided by the present application creates a stroke that moving part  1970  moves inside the neck part of the shell component  1980  along the axis of the stylus. Accordingly, the tip section  230  touching the moving part  1970  also moves the same distance of the stroke along the axis. The distance of the stroke could be varied according to different designs, e.g., 1 mm or 0.5 mm. The present invention does not limit the distance of the stroke. 
     In the rear of the rear moving part  1972 , a dielectric film  1973  is formed. In the rear of the dielectric film  1973 , a compressible conductor  1974  is arranged. In one embodiment, the compressible conductor  1974  may be a conductive rubber or an elastic element formed by conductors. A sandwich structure comprising the moving part  1970 , the dielectric film  1973 , and the compressible conductor  1974  makes a capacitor or a FSC. The FSC provided by the present invention may be applicable to the first capacitor  221  shown in  FIG.  2    through  FIG.  5   . In short, the FSC disclosed in the present application could be used in the embodiments mentioned above. 
     The compressible conductor  1974  is attached to a conductor base  1975  which is further attached to an inner face of the shell component  1980  by fasteners. In case the moving part  1970  moves toward rear side or right hand side, the compressible conductor  1974  is compressed by the rear moving part  1972  because the conductor base  1975  is fixed. Thus the capacitance of the FSC is changed accordingly. 
     Because of the restriction of stylus shape, circuits and battery module may be placed in the rear of the conductor base  1975 . As shown in  FIG.  19 A , those components are represented by a PCB  1990 . As a first plate of the FSC, the moving part  1970  is connected to the PCB  1990  through a moving part wire  1977 . As a second plate of the FSC, the conductor base  1975  is connected to the PCB  1990  through a base wire  1976 . 
     The base wire  1976  may be another elastic element. In some embodiments, the base wire  1976 , unlike the one shown in  FIG.  19 A , is surrounded the conductor base  1975 . In other embodiments, the conductor base  1975  is not conductive. Hence the base wire  1976  is electrically coupling to the compressible conductor  1974  through the conductor base  1975 . 
     In one embodiment, the manufacturing method of the dielectric film  1973  is submerging the right hand side surface of the rear moving part  1972  in a dielectric liquid. After the liquid stayed on the surface dried, a dielectric film  1973  is naturally formed on the right hand side surface of the rear moving part  1972 . 
     Please refer to  FIG.  20 (A) -(D), which show profiling diagrams of contact surface of the compressible conductor  1974  facing the dielectric film  1973 . The figure depicts four embodiments of the contact surface of the compressible conductor  1974  facing the dielectric film  1973 . The embodiment (A) shows a surface having a central bulge. The embodiment (C) shows a sloped surface. The embodiment (B) shows a conical surface. And the embodiment (D) illustrates a surface with multiple protruding bulges. The present application does not limit to the surfaces shown in those embodiments. 
     Although the surface attaching the dielectric film  1973  of the moving part  1970  is a plane surface, the present invention does not limit to that. The surface may be constructed as the surfaces shown in  FIG.  20 (A) -(D), such as having a central bulge, having multiple bulges, sloped, or conical. In other words, both the surfaces of the compressible conductor  1974  and the dielectric film  1973  are not planes in some embodiments. 
     Please refer to  FIG.  19 B , which shows an assembled profiling diagram of the structure shown in  FIG.  19 A . In the assembled structure, a single whole moving part  1970  is formed by the fore and the rear moving parts  1971  and  1972 . The moving part  1970  and the bearing of the shell component  1980  are connected by the elastic element  1978 . The elastic force provided by the elastic element  1978  pushes the moving part  1970  toward and touches the tip section  230  until portion of the bearing of the shell component  1980  is touched by the rear moving part  1972 . A stroke d of the moving part  1970  is relative to the shell component  1980 . In this situation, the compressible conductor  1974  is not deformed or compressed. It is assumed that a first capacitance value provided by the FSC. 
     Please refer to  FIG.  19 C , which shows another assembled profiling diagram of the structure shown in  FIG.  19 A . Comparing with  FIG.  19 B , the tip section  230  is pressed toward the rear side. Influenced by the movement of the tip section  230 , the moving part  1970  overcomes the force provided by the elastic element  1978  and moves the whole distance of the stroke d until the fore moving part  1971  touches the bearing of the shell component  1980 . In this situation, the compressible conductor  1974  is compressed by the moving part  1970  and the dielectric film  1973  and deformed. It is assumed that a second capacitance value provided by the FSC is different to the first capacitance value. 
     Between the positions shown in  FIGS.  19 B and  19 C , countless positions the moving part  1970  can stay. In other words, there exist countless compressible levels of the compressible conductors  1974 . Or the area of contact surface between the compressible conductor  1974  and the dielectric film  1973  could be varied indefinitely. Each of the positions, the compressed levels, or the areas can be corresponding to a particular capacitance value of the FSC. 
     Please refer to  FIG.  19 D , which depicts a profiling diagram of the FSC structure used in the transmitter  110  in accordance with an embodiment of the present invention. Comparing to  FIG.  19 B , the difference is that the compressible conductor  1974  and the dielectric film  1973  exchange their positions. Nevertheless, in case the moving part  1970  moves to the rear side, the compressible conductor  1974  is compressible by the dielectric film  1973  and the conductor base  1975  and deformed. The capacitance value of the FSC is changed accordingly. 
     Please refer to  FIG.  19 E , which depicts a profiling diagram of the FSC structure used in the transmitter  110  in accordance with an embodiment of the present invention. Comparing with  FIG.  19 B , the differences include that a compressible dielectric material  1979  rather than the dielectric film  1973  is place in the right hand side of the rear moving part  1972 . The compressible dielectric material  1979  may be dielectric rubber, plastic, foam or etc. The conductor attached to the conductor base  1975  is replaced by an incompressible conductor such as metal or graphite. When pressed by the moving part  1970 , the thickness of the compressible dielectric material  1979  decreases, the distance between the moving part  1970  and the conductor also decreases consequently. Hence the capacitance of the FSC is changed accordingly. However, the cost of the incompressible conductor shown in  FIG.  19 E  is more expensive than the compressible conductor shown in  FIG.  19 A . 
     In a variation of the embodiment shown in  FIG.  19 E , the contact surface of the conductor facing the compressible dielectric material  1979  may adopt those shown in  FIG.  20 (A) -(D). In another variation, the contact surface of the compressible dielectric material  1979  facing the conductor may adopt those shown in  FIG.  20 (A) -(D). 
     Similar to the embodiment shown in  FIG.  19 D , the positions of the compressible dielectric material  1979  and the conductor may be exchanged such that the compressible dielectric material  1979  is attached to the conductor base  1975  and the conductor is attached to the rear of the moving part  1970 . When the moving part  1970  moves to the rear side, the conductor causes the compressible dielectric material  1979  deformed such that the capacitance of the FSC is changed accordingly. 
     Please refer to  FIG.  21   , which illustrates a pressure sensor according to an embodiment of the present invention. As shown in the figure, the pressure sensor  2110  has two input terminals a and b and an output terminal c, which are all connected to a control unit  2120 . The control unit  2120  feeds signals with first frequency (group) F 1  and second frequency (group) F 2  into the input terminals a and b, respectively, and receives the output signal of the pressure sensor  2120 . The control unit  2120  may embody the method disclosed in  FIG.  6   . 
     When external pressure makes capacitance change of a capacitor C 1 , the control unit  2120  could deduce the pressure according to the capacitance change. Hence, the pressure sensor  2110  could be widely adapted to pressure measure devices such as weight sensor. In one application, the pressure sensor  2120  could be used in another form of stylus. After the pressure on the tip of the stylus is deduced, the control unit  2120  drives a signal transmitter for transmitting an electric signal with a predetermined frequency f 0  to a touch panel. 
     It is mentioned that the transmitter  110  may transmit the electric signal at some time after receiving the beacon signals emitted from the touch panel  120 , such that the touch panel  120  could detect the position of the transmitter  110  as well as the sensor states of the transmitter  110 . If no beacon signal is received during a first period, the transmitter  110  may enter a power saving mode. In this mode, the transmitter  110  detects the beacon signal every detection period. Once the beacon signal is detected, the transmitter  110  recovers back to normal working mode. The detection period is longer than the transmission period of the beacon signal. 
     Moreover, if no beacon signal is received during a second period in the power saving mode, the transmitter  110  may enter a sleep mode to turn off circuits and most parts until being waked up. In one embodiment of the present invention, in the sleep mode, the receiving circuit of the beacon signal and the transmitting circuit of the electric signal of the transmitter  110  are turned off. A button or a switch of the transmitter  110  could be used to wake itself up by user. In another embodiment of the present application, examples shown in  FIGS.  23 A,  23 B,  24 A, and  24 B  could be used to wake up the transmitter  110 . After the tip section  230  touches object, the voltage level of a connection port or GPIO 1  is raised to high from low such that the transmitter  110  begins to transmit electric signals. 
     In the present application, one function of the ring electrode  550  is to receive the beacon signal in additional to the tip section  230 . Since the surface area and volume of the ring electrode  550  is larger than the top of the tip section  230 , it can receive the beacon signal distant away from the touch panel. Or the touch panel  120  may transmit weaker beacon signal to save power consumption. If no beacon signal is received for a while, active stylus may enter deeper sleep mode to save more power. When in this sleep mode, user may recover the transmitter  110  back to the normal working mode by pressing the tip section  230 . Examples shown in  FIGS.  23 A,  23 B,  24 A, and  24 B  could be used to wake up the transmitter  110 . After the tip section  230  touches object, the voltage level of a connection port or GPIO 1  is raised to high from low such that the transmitter  110  begins to transmit electric signals. 
     When multiple transmitters  110  operate on one touch panel  120 , the touch panel  120  could transmit different beacon signals for corresponding transmitter  110  to emit its electric signal. The transmitter  110  may adjust the signal frequency or modulation of the first signal source  211 , the second signal source  212 , and the third signal source  513  according to different beacon signals such that the touch panel  120  could distinguish the source transmitter  110  of the received electric signals. Analogously, the different beacon signals may have different frequencies or different modulations. 
     Please refer to  FIG.  22   , which illustrates a pressure sensor according to an embodiment of the present invention. In this embodiment, the control unit  2220  may feed driving signal with a frequency to an input terminal c of the pressure sensor  2210  and receive currents with current values I 1  and I 2  corresponding to a first capacitor C 1  and a second capacitor C 2 , respectively. A ratio of these two current values is calculated by the control unit  2220 . Therefore a pressure level could be deduced accordingly. The control unit  2220  may embody the method shown in  FIG.  8   . In one application, the driving signal with the frequency is fed externally into the input terminal c of the pressure sensor  2220 . 
     Please refer to  FIGS.  23 A and  23 B , which depict profiling diagrams of a switch structure in accordance with an embodiment of the present invention. In the embodiment shown in  FIG.  23 A , there are three circuit boards. As seen in previous figures, there is a ramp at the right hand side. Before the ramp pushes to left, the circuit on the upper circuit board connects to the circuit on the lower circuit board through the circuit on the middle circuit board. A first contact point p 1  of the upper circuit board is coupled to a voltage source Vdd and a first connection port (GPIO 1 ). If no displacement vertical to the axis of the stylus, the first contact point p 1  is contacted with a second contact point p 2  on the middle circuit board. There is also a third contact point p 3  on the middle circuit board coupled to the second contact point p 2 . A fourth contact point p 4  of the lower circuit board is coupled to a ground level and a second connection port (GPIO 2 ). Besides, the fourth contact point p 4  is electrically coupled to the third contact point p 3 . There is a resistor between the power source Vdd and the first connection port (GPIO 1 ). If the circuit between the upper and the middle circuit boards is shorted, i.e., the first contact point p 1  contacts with the second contact point p 2 , and the circuit between the middle and lower circuit boards is shorted, i.e., the third contact point p 3  contacts with the fourth contact point p 4 , the voltage level of the first connection port (GPIO 1 ) is low or ground. 
     Please refer to  FIG.  23 B , after the ramp is pressed, the movement of the ramp deforms the contacting parts of the upper and the lower circuit boards. Due to the deformations, the circuit between the upper and the middle circuit boards is open, i.e., the first contact point p 1  separates with the second contact point p 2 , and the circuit between the middle and lower circuit boards is open, i.e., the third contact point p 3  separates with the fourth contact point p 4 , the voltage level of the first connection port (GPIO 1 ) is high or as high as Vdd. 
     In response to the voltage level of the first connection port (GPIO 1 ) from low to high, the transmitter  110  in sleep mode is waked up. Already seen in previous figures, supporting elements corresponding to the upper and the lower circuit boards help to recover these two circuit boards&#39; position, respectively, if the pressure of the ramp disappears. At this moment, the voltage level of the first connection turns to low from high. The first and the second connection ports may be pins of processor in the transmitter  110 . 
     Please refer to  FIGS.  24 A and  24 B , which depict profiling diagrams of a switch structure in accordance with an embodiment of the present invention. The embodiment shown in  FIGS.  23 A and  23 B  has two potential openings. No matter which opening is open, it turns the voltage level of the first connection to high from low. However, the embodiment shown in  FIGS.  24 A and  24 B , only one potential opening is presented. The circuit along the middle circuit board connects to ground. In case the circuit between the upper and the middle circuit board is shorted, the voltage level of the first connection port is low or ground. Instead, if the circuit between the upper and the middle circuit board is open, the voltage level of the first connection port is high or as high as Vdd. In the embodiment shown in  FIGS.  24 A and  24 B , the second contact point p 2  is electrically coupled to the second connection port (GPIO 2 ). 
     Please refer to  FIG.  25   , which shows a diagram for calculating the tip position. There are two transmitters  110  shown in  FIG.  25   , both include the ring electrode  550  and the tip section  230 . The left-hand side transmitter  110  is perpendicular to the touch panel  120 , the angle is approaching or equals to 90 degree. The angle between the right-hand side transmitter  110  and the touch panel  120  is less than 90 degree. Moreover, a transparent surface layer of the touch panel  120  has a thickness. Normally, the transparent surface layer is a reinforced glass. A display layer is underneath the transparent surface layer. 
     Since the transmitters  110  emits electric signals via the ring electrode  550  and/or the tip section  230  during the time period R, the touch sensitive processing apparatus  130  could calculate a centroid position R_cg of the electric signals which is corresponding to a centroid position of the ring electrode  550  and/or the tip section  230  projecting to the touch panel  120 . After that, during the time periods T 0  and T 1 , transmitter  110  emits electric signals only via the tip section  230 . Similarly, the touch sensitive processing apparatus  130  could calculate a centroid position Tip_cg of the electric signals which is corresponding to a centroid position of the tip section  230  projecting to the touch panel  120 . 
     For the left-hand side transmitter  110  shown in  FIG.  25   , since it is perpendicular to the touch panel  120 , the position R_cg equals or is approaching to the position Tip_cg. Thus, a position Tip_surface where the top of the tip section  230  touches the transparent surface layer of the touch panel  120  equals or is approaching to the positions R_cg and Tip_cg. Moreover, a position Tip_display where the top of the tip section  230  projects on the display layer of the touch panel  120  equals or is approaching to the positions, R_cg, Tip_cg, and Tip_surface. 
     For the right-hand side transmitter  110  shown in  FIG.  25   , there exist an inclination angle between the transmitter  110  and the touch panel  120 . Thus the position R_cg is not equal to the position Tip_cg. More distant between the positions R_cg and Tip_cg, the inclination angle is larger. Depends on the implementations of the transmitter  110 , the inclination angle or positions Tip_surface where the top of the tip section  230  touches the transparent surface layer of the touch panel  120  or Tip_display where the top of the tip section  230  projects on the display layer of the touch panel  120  could be found by the touch sensitive processing apparatus  130  via calculating or checking a look-up table according to the positions R_cg and Tip_cg. 
     Please refer to  FIG.  26   , which depicts a flow chart diagram for calculating the inclination angle in accordance with the present invention. The embodiment is applicable to the transmitter  110  having a ring electrode  550  shown in  FIG.  5   . It is also applicable to the signal modulations shown in  FIGS.  9 E and  9 F . The method could be performed by the touch sensitive processing apparatus  130  shown in  FIG.  1   . The embodiment shown in  FIG.  25    could be reference, too. 
     In step  2610 , calculating a first centroid position R_cg according to the ring electrode  550  and/or the tip section  230  projecting to the touch panel  120 . In step  2620 , calculating a second centroid position Tip_cg according to the tip section  230  projecting to the touch panel  120 . The present invention does not limit the executing order of these two steps  2610  and  2620 . Next, in optional step  2630 , calculating an inclination angle according to the first and the second centroid positions R_cg and Tip_cg. In optional step  2640 , calculating a position Tip_surface where the top of the tip section  230  touches the transparent surface layer of the touch panel  120  according to the first and the second centroid positions R_cg and Tip_cg. In optional step  2650 , calculating a position Tip_display where the tip section  230  projects on the display layer of the touch panel  120  according to the first and the second centroid positions R_cg and Tip_cg. Not all but at least one of steps  2630 ,  2640 , and  2650  has to be performed in the embodiment. And the present invention does not limit the executing order of these three steps  2630 ,  2640 , and  2650 . 
     Please refer to  FIGS.  27 ( a )-( e ) , which show embodiments of how display interface reflects stroke according to the inclination angle and/or pressure of the tip section. There exists 5 rows of embodiments (a) through (e) shown in  FIGS.  27 ( a )-( e ) . Each row comprises three examples corresponding to three inclination angles. The examples of the most left column are corresponding to which the active stylus is perpendicular to the touch sensitive panel. The examples of the most right column are corresponding to an inclination angle larger than another inclination angle corresponding to the examples of the middle column. The so-called stroke in the present invention usually refers to a rendering area on the display by image processing software. 
     Please be noted that in the embodiment, it is not required to utilize the embodiment using the ring electrode shown in  FIGS.  25  and  26    to calculate the inclination angle and positions Tip_surface and Tip_display. In one embodiment, other forms of sensor may be installed on the active stylus to measure the inclination angle. For example, IMU, inertial measurement unit, gyroscope, and accelerometer made by microelectronics technology are configured to measure the inclination angle and report it and/or derived data to computer system comprising the touch sensitive panel via wired or wireless communication. Therefore the computer system could implement the embodiments shown in  FIGS.  27 ( a )-( e ) . The fore-mentioned wired or wireless communication may follow industrial or proprietary standards such as Bluetooth or Wireless USB etc. 
     Now assuming that active stylus touches the touch panel using the same pressure level in those embodiments shown in  FIGS.  27 ( a )-( e ) . In some embodiments, each intersection point of vertical and horizontal lines represents the position Tip_surface corresponding to where the top of the tip section touches the transparent surface layer of the touch sensitive panel. In other embodiments, each intersection point of vertical and horizontal lines denotes the position Tip_cg corresponding to where the centroid of the tip. Of course, they may represent the locations Tip_display where the tip projects on the display layer of the touch sensitive panel. For convenience, those three positions are collectively named as a representative point, Tip. In other words, the representative point Tip may be one of the points, Tip_display, Tip_surface, or Tip_cg. 
     In the embodiment (a), in response to the increase of the inclination angle, the stroke shape changes from circle to ellipse. In other words, the distance between two focal points of the ellipse is corresponding to the inclination angle. The inclination angle increases with the distance between two focal points of the ellipse. Center of the ellipse is corresponding to the representative point Tip. 
     The difference between the embodiments (b) and (a) is that one intersection point of the semi-major axis and the ellipse is corresponding to the representative point Tip. The difference between the embodiments (c) and (a) is that one of the focal point of the ellipse is corresponding to the representative point Tip. The difference between the embodiments (d), (e), and (a) is that the stroke shape changes from ellipse to tear drop. Top of the tear drop of the embodiment (d) is corresponding to the representative point Tip. Somewhere from the top toward the end of the tear drop of the embodiment (e) is corresponding to the representative point Tip. 
     Although shown in  FIGS.  27 ( a )-( e ) , two stroke shapes and different points corresponding to the intersection point are enumerated. The present invention does not limit the stroke shape and the types of the representative point. In addition, in one embodiment, pressure of the tip may control the size of the shape. For example, the pressure may be corresponding to radius of circle or the distance between the focal points of the ellipse. In summarized, human-machine interface can change display content according to pressure of the tip and/or inclination angle of the active stylus. 
     In additional to change the stroke shape, the pressure of the tip and/or inclination angle of the stylus may be corresponding to different commands. For example of 3 dimensional design software, color temperature, strength, or scope of illuminating source could be changed according to the inclination angle. Or in case an object is selected by touch of the tip, orientation of the selected object could be changed according to direction of the inclination angle. Moreover, direction of the selected object could be rotated according to the inclination angle. 
     It is worthy noted that relation of the inclination angle and corresponding value is not limited as linearly in the present invention. In some embodiments, the relation may be non-linear and could be found in a lookup table or calculated in the quadratic function. 
     Please refer to  FIG.  28 ( a )-( b ) , which depict other embodiments of how display interface reflects stroke according to the inclination angle and/or pressure of the tip. It depicts two embodiments (a) and (b) which include left and right strokes, respectively. The inclination angle of the left hand side stroke is zero. The stroke includes five circles C 1  through C 5  with increasing radius. The sizes of the circles are based on the pressure values of the tip. The inclination angle of the right hand side stroke is a non-zero constant. The stroke includes five ellipses E 1  through E 5  with increasing major and minor radius. Sizes of the ellipses E 1  through E 5  depend on the pressure values of the tip which are as the same as corresponding the circles C 1  through C 5 . In addition, semi-major axes of these ellipses E 1  through E 5  are 30 degrees off horizontal according to direction of the inclination angle. The direction of the inclination angle and the stroke direction are different. In this figure, these two directions are off a 15-degree angle. 
     The embodiment (a) shown in  FIGS.  28 ( a )-( b )  is corresponding to the embodiment (a) shown in  FIGS.  27 ( a )-( e ) , i.e., center of the ellipse is corresponding to the representative point Tip. Analogously, the embodiment (b) shown in  FIGS.  28 ( a )-( b )  is corresponding to the embodiment (b) shown in  FIGS.  27 ( a )-( e ) , i.e., the intersection point between the semi-major axis and the ellipse is corresponding to the representative point Tip. Could be seen in these two embodiments shown in  FIGS.  28 ( a )-( b ) , under the same pressure level, the stroke shapes are different according to different inclination angles. In consequence, strokes of some soft and flexible tips such as brush pen and quill pen could be simulated according to the pressure level and inclination angle. 
     In one embodiment of this invention, the parallel intervals between the first and the second electrodes  121  and  122  of the touch panel  120  are larger than the tip of the tip section  230 . As shown in  FIG.  25   , when the tip of the tip section  230  inclines, it is likely to have the larger contact area with the touch panel  120 . However, in one typical example, the diameter of the above-mentioned tip contact area is 1 mm at most. The interval between two adjacent first electrodes  121  or second electrodes  122  can be 4 mm to 5 mm. In other words, the chance of the tip section  230  being located above the first electrodes  121  or second electrodes  122  is much smaller than the chance of the tip section  230  being located between them. 
     As shown in  FIG.  35 (A) -(B), illustrate signal strength of a transmitter in accordance with an embodiment of the present invention. The part (A) in the upper figure is one part of the touch panel  120 , including two adjacent first electrodes  121   a  and  121   b . When the touch sensitive processing apparatus  130  detects one strength ratio value of electric signal sent by the transmitter  110  to gain the pressure of the tip section  230 , it respectively detects the electric signals sensed by all first electrodes  121 . When the tip section  230  on the touch panel  120  has the moving trail  3510  and assumed the electric signals emitted with the same strength, the strength of corresponding electric signals gained by the touch sensitive processing apparatus  130  is possibly shown as the part (b), which is a sine wave line  3520 . 
     As shown in the part (B) of  FIG.  35   , when the tip section  230  approaches to or hovers above the first electrode  121   a  or  121   b , the total strength of the received electric signals is the biggest. When the tip section  230  is located between the two adjacent first electrodes  121   a  and  121   b , the total strength of the received electric signals is the smallest. In other words, when it hovers above the electrode, the SNR (signal-noise ratio) of the strength of the electric signals emitted by the transmitter  110  and the noise signals is the largest. Instead, when it is between the two adjacent electrodes, the SNR of the strength of the electric signals emitted by the transmitter  110  and noise signals of the transmitter  110  is the smallest. Since this invention can use the ratio value of the two frequent signals among the electric signals to estimate the sensing value of certain sensor, such as the pressure value of the tip section  230 . Despite any point of the signal strength  3520 , the ratio value in theory is the same. However, the samples of the low SNR that estimate the ratio may be influenced by the noise to increase the extent of the error. Therefore, one characteristic of this invention lies in choosing the samples of high signal strength or choosing the samples of high noise ratio in order to count the ratio value of the different signals included. By doing so, the sensing value of certain sensor could be deduced. 
     As shown in  FIG.  36   , it depicts a diagram of partitions for a touch panel  120  in accordance with an embodiment of the present invention. The touch sensitive processing apparatus  130  connects to multiple first electrodes  121  and multiple second electrodes  122  of the touch panel  120 . In one embodiment, the touch sensitive processing apparatus  130  can detect the electric signals of multiple first electrodes  121  separately or simultaneously and it can also detect the electric signals of multiple second electrodes  122  separately or simultaneously. 
     In one embodiment, the touch sensitive processing apparatus  130  can detect multiple first electrodes  121  and second electrodes  122  simultaneously. In this embodiment, when the tip section  230  of the transmitter  110  is located in around the intersection of the two first electrode  121  and second electrode  122  near the area  3610 ,  3630 ,  3670 , or  3690 , the signal strength detected by the first electrode  121  is approximately the same to of that detected by the second electrode  122 . For example, when the tip section  230  is located in the area  3670 , the signal strength detected either by the first electrode  121  or by the second electrode  122  is roughly the same. Likewise, when the tip section  230  is located in the area  3650 , the signal strength detected either by the first electrode  121  or by the second electrode  122  is roughly the same. 
     In this embodiment, when the tip section  230  is located in the area  3620  and/or the area  3680 , the signal strength detected by the first electrode  121  is larger than the signal strength detected by the second electrode  122 . Likewise, when the tip section  230  is located in the area  3640  and/or the area  3660 , the signal strength detected by the second electrode  122  is larger than the signal strength detected by the first electrode  121 . 
     In one embodiment, the touch sensitive processing apparatus  130  can respectively detect the multiple first electrodes  121  and second electrodes  122 . For instance, it first detects the first electrodes  121  and at this moment, the second electrodes  122  are grounded. On the contrary, when the multiple second electrodes  122  are detected, the first electrodes  121  are grounded. In this embodiment, when the tip section  230  of the transmitter  110  is located between the intersectional area, which is near the area  3610 ,  3630 ,  3670 , and  3690 , of the two first electrode  121  and second electrode  122 , the signal strength through the detection of the first electrode  121   a  is similar to the signal strength detected by the second electrode  122 . For example, when the tip section  230  is located in the area  3670 , the signal strength detected by the first electrode  121   a  and by the second electrode  122   b  is generally the same. Likewise, when the tip section  230  is located in the area  3650 , the signal strength detected by the first electrode  121  is equal to of that detected by the second electrode  122 . 
     In this embodiment, when the tip section  230  is located in the area  3620  and/or the area  3680 , the signal strength detected by the first electrode  121  is larger than the signal strength detected by the second electrode  122 . Similarly, when the tip section  230  is located in the area  3640  and/or the area  3660 , the signal strength detected by the second electrode  122  is larger than the signal strength detected by the first electrode  121 . Besides, half of the electrodes is grounded during the detecting process. Therefore, in one embodiment, if detected by the first electrode  121   a  or  121   b , the signal strength of the area  3650  that the tip section  230  is located in is larger than the signal strength of the area  3620  or  3680  where the tip section  230  is located because some parts of the electric signals sent by the tip section  230  are grounded via the grounded second electrode  122   a  or  122   b . Similarly, in another embodiment, if detected by the second electrode  122   a  or  122   b , the signal strength of the area  3650  that the tip section  230  is located in is larger than the signal strength of the area  3640  or  3660  where the tip section  230  is located since some parts of the electric signals sent by the tip section  230  are grounded via the grounded first electrode  122   a  or  122   b.    
     In the above-mentioned embodiment, when the located area of the tip section  230  is certain, the corresponding first electrode  121  or second electrode  122  can be chosen. In one embodiment, when the judged tip section  230  is located in the intersectional point of the first-categorized areas, such as the areas  3610 ,  3630 ,  3670 , and  3690 , of the first electrode  121  and the second electrode  122 , the electric signals of the corresponding first electrode  121  and the second electrode  122  can be chosen to be further analyzed. When the judged tip section  230  is located in the intersectional point of the second-categorized area, such as the area  3650 , of the first electrode  121  and the second electrode  122 , similarly, the electric signals of one of the corresponding four first electrodes  121  and the second electrodes  122  can be chosen to be further analyzed. For instance, one of the first electrodes  121   a ,  121   b , the second electrodes  122   a , and  122   b  can be chosen to have a further analysis. When the judged tip section  230  is located near the first electrode  121  or the second electrode  122  and is not located in the intersectional point of the third-categorized areas of the first electrode  121  and the second electrode  122 , the electric signals of the corresponding first electrode  121  or second electrode  122  can be chosen to be further analyzed. For instance, when the judged tip section  230  is located in the area  3630 , the electric signals of the second electrode  122   a  can be chosen to be further analyzed. When the judged tip section  230  is located in the area  3680 , the electric signals of the second electrode  122   b  can be chosen to be further analyzed. When the judged tip section  230  is located in the area  3640 , the electric signals of the first electrode  121   a  can be chosen to be further analyzed. When the judged tip section  230  is located in the area  3660 , the electric signals of the first electrode  121   b  can be chosen to be further analyzed. 
     In certain embodiments, the above analysis and estimation can include increasing the yield value of the chosen receiving terminal connected to the electrode in order to increase the SNR. Since the noise may come from the interior circuit of the receiving terminal, the noise from there can be a constant. Rising the yield value of the chosen electrode can increase the SNR. 
     In certain embodiments, the above analysis and estimation can include adding the signal value detected by the corresponding electrode, which may increase the SNR. Since the noise may come from the interior circuit of the receiving terminal, the noise from there can be a constant. Rising the yield value of the chosen electrode can increase the SNR. Adding the signal values detected by the adjacent electrodes can increase the SNR. For example, when the tip section  230  is located in the first-categorized and second-categorized areas mentioned above, the signal values detected by the adjacent electrodes can be added. For instance, the tip section  230  is located in the area  3650 , the signals of the first electrodes  121   a  and  121   b  can be added, so can be the second electrodes  122   a  and  122   b . Likewise, the signals of the first electrodes  121   a  and  121   b  as well as the signals of the second electrodes  122   a  and  122   b  can also be added. For instance, when the judged tip section  230  is located in the area  3610 , the signals of the first electrode  121   a  and the second electrode  122   b  can also be added. 
     In one embodiment, this invention can add signal value detected after the yield value become larger and then get one ratio value of the two frequency signals. 
     Suppose the touch panel  120  include M first electrodes  121  and N second electrodes  122 , the detected result of the touch sensitive processing apparatus  130  is M+N. Either one of the largest signal strengths can be directly chosen to have a further analysis, or multiple results of the largest signal strength can be added and then to have a further analysis. Besides, increasing the yield value from one or multiple electrodes with the largest signal strength to run next detection is also feasible. 
     It is noted that although each area shape shown in  FIG.  36    is a square, the invention is not limited the shape of each area. For example, the first-categorized area could be a rectangle, circle, or oval. The second-categorized area could be a square, rectangle, circle, or oval. The third-categorized area can be the remaining area of the subtraction of the previous two categories on the touch panel. 
     One aspect of the present application is to provide a transmitter which comprises: a first component for receiving signal with a first frequency group, wherein a first impedance of the first component changes according to a pressure; a second component for receiving signal with a second frequency group, wherein the second component has a second impedance; and a tip section for receiving outputs of the first component and the second component and transmitting an electric signal, wherein the tip section is used to receive the pressure. 
     In one embodiment, the second impedance is not changed according to the pressure. Alternatively, the second impedance is changed according to the pressure, too. 
     In one embodiment, the transmitter further comprises a third switch and a third component serially connected to the third switch, wherein the first component is connected with the third switch and the third component in parallel. The transmitter may further comprise a fourth switch and a fourth component serially connected to the fourth switch, wherein the first component is connected with the fourth switch and the fourth component in parallel. 
     Alternatively, the transmitter further comprises a third switch and a third component serially connected to the third switch, wherein the second component is connected with the third switch and the third component in parallel. The transmitter may further comprise a fourth switch and a fourth component serially connected to the fourth switch, wherein the second component is connected with the fourth switch and the fourth component in parallel. 
     In one embodiment, the first frequency group comprises one or more first frequency, the second frequency group comprises one or more second frequency. The first frequency is different from the second frequency. 
     In one embodiment, the first impedance equals to the second impedance if the pressure is absent. In one embodiment, the tip section does not touch anything if the pressure is absent. 
     In one embodiment, a ratio of a first signal strength M 1  corresponding to signal with the first frequency group and a second signal strength M 2  corresponding to signal with the second frequency group is related to the pressure. The ratio is one of the followings: M 1 /M 2 , M 2 /M 1 , M 1 /(M 1 +M 2 ), M 2 /(M 1 +M 2 ), (M 1 −M 2 )/(M 1 +M 2 ), and (M 2 −M 1 )/(M 1 +M 2 ). 
     In one embodiment, if the ratio equals or falls into a first range, the pressure is absent. If the ratio equals or falls into a second range, the third switch is shorted and the first component is connected with the third component in parallel. If the ratio equals or falls into a third range, the fourth switch is shorted and the first component is connected with the fourth component in parallel. If the ratio equals or falls into a fourth range, the third switch and the fourth switch are shorted and the first component is connected with the third component and the fourth component in parallel. Alternatively, if the ratio equals or falls into a fifth range, the third switch is shorted and the second component is connected with the third component in parallel. If the ratio equals or falls into a sixth range, the fourth switch is shorted and the second component is connected with the fourth component in parallel. If the ratio equals or falls into a seventh range, the third switch and the fourth switch are shorted and the second component is connected with the third component and the fourth component in parallel. 
     In one embodiment, the first component is a force sensitive capacitor. The second component is a capacitor. 
     In one embodiment, the transmitter further comprises a ring electrode surrounding the tip section. The ring electrode is not electrically coupled to the tip section. In one embodiment, the ring electrode comprises one or more separate electrodes. 
     One aspect of the present application is to provide a transmitting method for a transmitter, which comprises a first component, a second component, and a tip section. The tip section is used to receive the outputs of the first and the second components. The method comprises changing a first impedance of the first component according to a pressure on the tip section; providing signal with a first frequency group to the first component; providing signal with a second frequency group to the second component; and transmitting an electric signal from the tip section. 
     One aspect of the present application is to provide a method for determining a pressure received by a transmitter, comprises: receiving an electric signal transmitted from the transmitter; calculating a first signal strength M 1  corresponding to signal with a first frequency group contained in the electric signal; calculating a second signal strength M 2  corresponding to signal with a second frequency group contained in the electric signal; calculating the pressure based on a ratio of the first signal strength M 1  and the second signal strength M 2 . 
     In one embodiment, the step of calculating the pressure may comprises one of the followings: looking into a lookup table, linear interpolation, and quadratic curve interpolation 
     In one embodiment, the method further comprises determining the state of the third switch according to the ratio. Alternatively, the method further comprises determining the state of the fourth switch according to the ratio. 
     One aspect of the present application is to provide a touch sensitive processing apparatus for determining a pressure received by a transmitter, comprises: an interface configured to connect to a plurality of first electrodes and a plurality of second electrodes of a touch panel, wherein multiple sensing points are located where the intersections of the first and second electrodes; at least one demodulator for calculating a first signal strength M 1  and a second signal strength M 2  corresponding to signal with a first frequency group and signal with a second frequency group contained in the electric signal, respectively; and a calculating unit for calculating the pressure based on a ratio of the first signal strength M 1  and the second signal strength M 2 . 
     In one embodiment, the calculating unit further determining the state of the third switch according to the ratio. Alternatively, the calculating unit further determining the state of the fourth switch according to the ratio. 
     One aspect of the present application is to provide a touch sensitive system for determining a pressure received by a transmitter, comprises: the transmitter, a touch panel; and a touch sensitive processing apparatus, the transmitter comprises: a first component for receiving signal with a first frequency group, wherein a first impedance of the first component changes according to a pressure; a second component for receiving signal with a second frequency group, wherein the second component has a second impedance; and a tip section for receiving outputs of the first component and the second component and transmitting an electric signal, wherein the tip section is used to receive the pressure. The touch panel comprises a plurality of first electrodes and a plurality of second electrodes, wherein multiple sensing points are located where the intersections of the first and second electrodes. The touch sensitive processing apparatus comprises: an interface configured to connect to the plurality of first electrodes and the plurality of second electrodes of the touch panel; at least one demodulator for calculating a first signal strength M 1  and a second signal strength M 2  corresponding to signal with a first frequency group and signal with a second frequency group contained in the electric signal, respectively; and a calculating unit for calculating the pressure based on a ratio of the first signal strength M 1  and the second signal strength M 2 . 
     One aspect of the present application is to provide a transmitter, comprises: a first component for receiving a signal source, wherein a first impedance of the first component changes according to a pressure; a second component for receiving the signal source, wherein the second component has a second impedance; a tip section for receive the pressure; and a control unit for calculating a first current value I 1  and a second current value I 2  from the first component and the second component, respectively, and calculating the pressure according to a ratio of the first current value I 1  and the second current value I 2 ; and a communication unit for transmitting the pressure value. 
     In one embodiment, the second impedance is not changed according to the pressure. Alternatively, the second impedance is changed according to the pressure, too. 
     In one embodiment, the communication unit comprises a wireless communication unit for transmitting the pressure value. Alternatively, the communication unit comprises a wired communication unit for transmitting the pressure value. 
     In one embodiment, the signal source is the wired communication unit. In one embodiment, the signal source is a signal received from the tip section. 
     In one embodiment, the ratio is corresponding to the pressure. The ratio may be one of the followings: I 1 /I 2 , I 2 /I 1 , I 1 /(I 1 +I 2 ), I 2 /(I 1 +I 2 ), (I 1 −I 2 )/(I 1 +I 2 ), and (I 2 −I 1 )/(I 1 +I 2 ). 
     In one embodiment, the first impedance equals to the second impedance if the pressure is absent. 
     In one embodiment, the transmitter further comprises a third switch and a third component serially connected to the third switch, wherein the first component is connected with the third switch and the third component in parallel. The transmitter may further comprise a fourth switch and a fourth component serially connected to the fourth switch, wherein the first component is connected with the fourth switch and the fourth component in parallel. In one embodiment, if the ratio equals or falls into a first range, the pressure is absent. If the ratio equals or falls into a second range, the third switch is shorted and the first component is connected with the third component in parallel. If the ratio equals or falls into a third range, the fourth switch is shorted and the first component is connected with the fourth component in parallel. If the ratio equals or falls into a fourth range, the third switch and the fourth switch are shorted and the first component is connected with the third component and the fourth component in parallel. 
     Alternatively, the transmitter further comprises a third switch and a third component serially connected to the third switch, wherein the second component is connected with the third switch and the third component in parallel. The transmitter may further comprise a fourth switch and a fourth component serially connected to the fourth switch, wherein the second component is connected with the fourth switch and the fourth component in parallel. Alternatively, if the ratio equals or falls into a fifth range, the third switch is shorted and the second component is connected with the third component in parallel. If the ratio equals or falls into a sixth range, the fourth switch is shorted and the second component is connected with the fourth component in parallel. If the ratio equals or falls into a seventh range, the third switch and the fourth switch are shorted and the second component is connected with the third component and the fourth component in parallel. 
     In one embodiment, the control unit further determining the state of the third switch according to the ratio. Alternatively, the control unit further determining the state of the fourth switch according to the ratio. 
     In one embodiment, the communication unit further transmits the state of the third switch. Alternatively, the communication unit further transmits the state of the fourth switch. 
     One aspect of the present application is to provide a transmitting method for a transmitter, which comprises a first component, a second component, and a tip section. The tip section is used to receive the outputs of the first and the second components. The method comprises changing a first impedance of the first component according to a pressure on the tip section; providing a signal source to the first component and the second component; calculating a first current value I 1  and a second current value I 2  from the first component and the second component, respectively; and calculating the pressure according to a ratio of the first current value I 1  and the second current value I 2 ; and transmitting the pressure value. 
     One aspect of the present application is to provide a touch sensitive system for determining a pressure received by a transmitter, comprises: the transmitter; and a host. The transmitter comprises: a first component for receiving a signal source, wherein a first impedance of the first component changes according to a pressure; a second component for receiving the signal source, wherein the second component has a second impedance; a tip section for receiving the pressure; and a control unit for calculating a first current value I 1  and a second current value I 2  from the first component and the second component, respectively, and calculating the pressure according to a ratio of the first current value I 1  and the second current value I 2 ; and a communication unit for transmitting the pressure value to the host. The host comprises a host communication unit for receiving the pressure value. 
     In one embodiment, the touch sensitive system further comprises a touch panel and a touch sensitive processing apparatus, wherein the touch sensitive processing apparatus coupled to the touch panel is configured to detect a position the transmitter is relative to the touch panel and to send the position to the host. 
     In one embodiment, the control unit further determining the state of the third switch according to the ratio. Alternatively, the control unit further determining the state of the fourth switch according to the ratio. In one embodiment, the communication unit further transmits the state of the third switch to the host. Alternatively, the communication unit further transmits the state of the fourth switch to the host. In one embodiment, the host communication unit is configured to receive the state of the third switch. Alternatively, the host communication unit is configured to receive the state of the fourth switch. 
     One aspect of the present application is to provide a force sensor, comprises a first input terminal for receiving signal with a first frequency group; a second input terminal for receiving signal with a second frequency group; and an output terminal for transmitting an electric signal, wherein a ratio of a first signal strength M 1  and a second signal strength M 2  corresponding to signal with a first frequency group and signal with a second frequency group contained in the electric signal, respectively, is corresponding to a pressure. 
     In one embodiment, the ratio is one of the followings: M 1 /M 2 , M 2 /M 1 , M 1 /(M 1 +M 2 ), M 2 /(M 1 +M 2 ), (M 1 −M 2 )/(M 1 +M 2 ), and (M 2 −M 1 )/(M 1 +M 2 ). 
     In one embodiment, the force sensor further comprises a third switch. In one embodiment, if the ratio equals or falls into a first range, the pressure is absent. If the ratio equals or falls into a second range, the third switch is shorted. 
     Alternatively, the force sensor further comprises a fourth switch. In one embodiment, if the ratio equals or falls into a third range, the fourth switch is shorted. If the ratio equals or falls into a fourth range, the third switch and the fourth switch are shorted. 
     One aspect of the present application is to provide a force sensor, comprises an input terminal for receiving a signal source; a first output terminal for outputting signal with a first current value I 1 ; and a second output terminal for outputting signal with a second current value I 2 , wherein a ratio of the first current value I 1  and the second current value I 2  is corresponding to a pressure. 
     In one embodiment, the ratio may be one of the followings: I 1 /I 2 , I 2 /I 1 , I 1 /(I 1 +I 2 ), I 2 /(I 1 +I 2 ), (I 1 −I 2 )/(I 1 +I 2 ), and (I 2 −I 1 )/(I 1 +I 2 ). 
     In one embodiment, the force sensor further comprises a third switch. In one embodiment, if the ratio equals or falls into a first range, the pressure is absent. If the ratio equals or falls into a second range, the third switch is shorted. 
     Alternatively, the force sensor further comprises a fourth switch. In one embodiment, if the ratio equals or falls into a third range, the fourth switch is shorted. If the ratio equals or falls into a fourth range, the third switch and the fourth switch are shorted. 
     One aspect of the present application is to provide a force sensor, comprises: a first circuit board containing a first metal plate for receiving signal with a first frequency group; a second circuit board in parallel with the first circuit board, containing a second metal plate and a third metal plate which are intact, wherein the third metal plate for receiving signal with a second frequency group, the second metal plate for outputting an electric signal, wherein the second metal plate is in the middle of the first and the third metal plates; and a ramp means for bending the first circuit board upward. 
     One aspect of the present application is to provide a force sensor, comprises: a first circuit board containing a first metal plate for outputting signal with a first current value I 1 ; a second circuit board in parallel with the first circuit board, containing a second metal plate and a third metal plate which are intact to each other, wherein the third metal plate for outputting signal with a second current value I 2 , the second metal plate for receiving a signal source, wherein the second metal plate is in the middle of the first and the third metal plates; and a ramp means for bending the first circuit board upward. 
     In one embodiment, part of the first metal plate is located in the bent part of the first circuit board. 
     In one embodiment, the force sensor further comprises a supporting element for supporting the first circuit board. 
     In one embodiment, the first metal plate, the second metal plate, and the third metal plate are in parallel. Alternatively, the distance between the first and the second metal plate equals to the distance between the second metal plate and the third metal plate. 
     In one embodiment, a first capacitor is formed by the first and the second metal plates; a second capacitor is formed by the second and the third metal plates. Alternatively, the impedance of the first capacitor equals to the impedance of the second capacitor if the first circuit board is not bending. 
     In one embodiment, both the first and the second circuit boards are printed circuit boards. 
     One aspect of the application is to provide a force sensor, comprises a first circuit board containing a first metal plate and a third metal plate which are intact to each other for receiving signal with a first frequency group and signal with a second frequency group, respectively; a second circuit board in parallel with the first circuit board containing a second metal plate for outputting an electric signal; and a ramp means for bending the first circuit board upward. 
     One aspect of the application is to provide a force sensor, comprises a first circuit board containing a first metal plate and a third metal plate which are intact to each other for outputting signal with a first current value and signal with a second current value, respectively, a second circuit board in parallel with the first circuit board containing a second metal plate for receiving a signal source; and a ramp means for bending the first circuit board upward. 
     In one embodiment, the force sensor further comprises a supporting element for supporting the first circuit board. 
     In one embodiment, the first metal plate is in parallel with the second metal plate; the second metal plate is in parallel with the third metal plate. Alternatively, the distance between the first and the second metal plate equals to the distance between the second metal plate and the third metal plate. 
     In one embodiment, a first capacitor is formed by the first and the second metal plates; a second capacitor is formed by the second and the third metal plates. Alternatively, the impedance of the first capacitor equals to the impedance of the second capacitor if the first circuit board is not bending. 
     In one embodiment, both the first and the second circuit boards are printed circuit boards. 
     One aspect of the application is to provide a force sensor, comprises a first circuit board containing a first metal plate and a third metal plate which are intact to each other for receiving signal with a first frequency group and signal with a second frequency group, respectively; a second circuit board in parallel with the first circuit board containing a second metal plate for outputting an electric signal; a third circuit board in parallel with the second circuit board, containing a fourth metal plate and a fifth metal plate which are intact to each other for receiving signal with the first frequency group and signal with the second frequency group, respectively; and a ramp means for bending the first circuit board upward and bending the third circuit board downward. 
     In one embodiment, the force sensor further comprises a first supporting element for supporting the first circuit board. In one embodiment, the force sensor further comprises a second supporting element for supporting the third circuit board. 
     In one embodiment, the first metal plate is in parallel with the second metal plate; the second metal plate is in parallel with the third metal plate; the fourth metal plate is in parallel with the second metal plate; the fifth metal plate is in parallel with the second metal plate. Alternatively, the distance between the first and the second metal plate equals to the distance between the second metal plate and the third metal plate. The distance between the fourth and the second metal plate equals to the distance between the second metal plate and the fifth metal plate. 
     In one embodiment, the first metal plate is on top of the fourth metal plate. Alternatively, the third metal plate is on top of the fifth metal plate. 
     In one embodiment, area of the first metal plate equals to area of the fourth metal plate. Alternatively, area of the third metal plate equals to area of the fifth metal plate. 
     In one embodiment, a first capacitor is formed by the first and the second metal plates; a second capacitor is formed by the second and the third metal plates; a third capacitor is formed by the fourth and the second metal plates; a fourth capacitor is formed by the second and the fifth metal plates. Alternatively, the impedance of the first capacitor equals to the impedance of the second capacitor if the first circuit board is not bending. Alternatively, the impedance of the third capacitor equals to the impedance of the fourth capacitor if the third circuit board is not bending. Alternatively, the impedance of the first capacitor equals to the impedance of the third capacitor, the impedance of the second capacitor equals to the impedance of the fourth capacitor. 
     In one embodiment, the first, the second, and the third circuit boards are all printed circuit boards. 
     One aspect of the application is to provide a force sensor, comprises a first circuit board containing a first metal plate for receiving signal with a first frequency group; a second circuit board in parallel with the first circuit board, containing a second metal plate, a third metal plate, a fourth metal plate and a fifth metal plate, which are intact and parallel to each other, wherein the third metal plate and the fourth metal plate for receiving signal with a second frequency group, wherein the second metal plate is coupled to the fifth metal plate for outputting an electric signal; a third circuit board containing a sixth metal plate for receiving signal with the first frequency board, wherein the second circuit board is placed in between the first and the third circuit boards; and a ramp means for bending the first circuit board upward and bending the third circuit board downward. 
     In one embodiment, the force sensor further comprises a first supporting element for supporting the first circuit board. In one embodiment, the force sensor further comprises a second supporting element for supporting the third circuit board. 
     In one embodiment, the first metal plate is in parallel with the second metal plate; the second metal plate is in parallel with the third metal plate; the fourth metal plate is in parallel with the fifth metal plate; and the fifth metal plate is in parallel with the six metal plate. Alternatively, the distance between the first and the second metal plate equals to the distance between the second metal plate and the third metal plate. The distance between the fourth and the fifth metal plate equals to the distance between the fifth metal plate and the sixth metal plate. 
     In one embodiment, the first metal plate is on top of the sixth metal plate. 
     In one embodiment, area of the first metal plate equals to area of the sixth metal plate. Alternatively, area of the second metal plate equals to area of the fifth metal plate. Alternatively, area of the third metal plate equals to area of the fourth metal plate. 
     In one embodiment, a first capacitor is formed by the first and the second metal plates; a second capacitor is formed by the second and the third metal plates; a third capacitor is formed by the fourth and the fifth metal plates; a fourth capacitor is formed by the fifth and the sixth metal plates. Alternatively, the impedance of the first capacitor equals to the impedance of the second capacitor if the first circuit board is not bending. Alternatively, the impedance of the third capacitor equals to the impedance of the fourth capacitor if the third circuit board is not bending. Alternatively, the impedance of the first capacitor equals to the impedance of the fourth capacitor, the impedance of the second capacitor equals to the impedance of the third capacitor. 
     In one embodiment, the first, the second, and the third circuit boards are all printed circuit boards. 
     One aspect of the application is to provide a force sensor, comprises: a first metal plate, a second metal plate, and third metal plate which are intact and sequentially parallel to each other, wherein the first metal plate for receiving signal with a first frequency group, the third metal plate for receiving signal with a second frequency group, the second metal plate for outputting an electric signal, wherein one end of the second metal plate is bendable. 
     One aspect of the application is to provide a force sensor, comprises: a first metal plate, a second metal plate, and third metal plate which are intact and sequentially parallel to each other, wherein the first metal plate for outputting signal with a first current value, the third metal plate for outputting signal with a second current value, and the second metal plate for receiving a signal source, wherein one end of the second metal plate is bendable. 
     In one embodiment, the distance between the first metal plate and the second metal plate equals to the distance between the second metal plate and the third metal plate. 
     In one embodiment, a first capacitor is formed by the first and the second metal plates; a second capacitor is formed by the second and the third metal plates. Alternatively, the impedance of the first capacitor equals to the impedance of the second capacitor if the second circuit board is not bending. 
     One aspect of the application is to provide a force sensor, comprises: a first metal plate, a second metal plate, and third metal plate which are intact and sequentially parallel to each other, wherein the first metal plate for outputting an electric signal, the second metal plate for receiving signal with a first frequency group, the third metal plate for receiving signal with a second frequency group, wherein one end of the first metal plate is bendable. 
     One aspect of the application is to provide a force sensor, comprises: a first metal plate, a second metal plate, and third metal plate which are intact and sequentially parallel to each other, wherein the first metal plate for receiving a signal source, the second metal plate for outputting signal with a first current value, the third metal plate for outputting signal with a second current value, wherein one end of the first metal plate is bendable. 
     In one embodiment, the distance between the first metal plate and the second metal plate equals to the distance between the second metal plate and the third metal plate. 
     In one embodiment, a first capacitor is formed by the first and the second metal plates; a second capacitor is formed by the second and the third metal plates. Alternatively, the impedance of the first capacitor equals to the impedance of the second capacitor if the first circuit board is not bending. 
     One aspect of the application is to provide a transmitter, comprises a moving part for moving a stroke along an axis of the transmitter; a dielectric material placing in the rear of the moving part; and a conductor placing in the rear of the dielectric material, wherein a force sensitive capacitor is formed by the moving part, the dielectric material, and the conductor. 
     In one embodiment, the transmitter further comprises a tip section placing in the fore of the moving part. In one embodiment, the tip section is a conductor coupling to the moving part. Alternatively, the tip section is configured to transmit an electric signal. The signal strength of certain frequency group contained in the electric signal relates to the impedance of the force sensing capacitor. 
     In one embodiment, the transmitter further comprises an elastic element and a shell component, wherein the elastic element is configured to provide elastic force between the moving part and the shell component such that the moving part is pushed to the fore end of the stroke by the elastic force. 
     In one embodiment, the dielectric material is a dielectric film. The conductor comprises a compressible conductor and a conductor base. Alternatively, the dielectric material is compressible dielectric material. 
     In one embodiment, a contact surface of the dielectric material facing the conductor comprises one of the following: a sloped surface, a surface with multiple bulges, a conical surface, and a surface with central bulge. Alternatively, a contact surface of the conductor facing the dielectric material comprises one of the following: a sloped surface, a surface with multiple bulges, a conical surface, and a surface with central bulge. 
     In one embodiment, the dielectric material and the conductor reside in an internal chamber of the shell component. Alternatively, the internal chamber is an empty cylinder. 
     In one embodiment, the moving part comprises a fore moving part and a rear moving part. The fore moving part contacts with the tip section and electrically couples to the tip section. 
     In one embodiment, the transmitter further comprises a circuit board which connects to the conductor via a base wire and connects to the moving part via a moving part wire. Alternatively, the moving part wire is coupled to the elastic element. 
     In one embodiment, the elastic element does not surround the moving part. Alternatively, the base wire does not surround the conductor. 
     One aspect of the application is to provide a circuit switch, comprises: a first circuit board, a second circuit board, a third circuit board which are intact and sequentially parallel to each other, and a dual ramp means, wherein a first end of the first circuit board and a first end of the third circuit board contacts with the two ramps of the dual ramp means, respectively, a first end of the second circuit board does not contact with the dual ramp means, the first end of the second circuit board comprises a circuit, a second point and a third point of the circuit contacts with and electrically couples to a first point of the first circuit board and a fourth point of the third circuit board, respectively. 
     In one embodiment, when the dual ramp means moves toward the second circuit board, the first circuit board and the third circuit board pressed by the dual ramp means and bent upward and downward, respectively, whereby the electrically coupling between the first point and the second point is open and the electrically coupling between the third point and the fourth point is open. 
     In one embodiment, the first point is connected with a first connection point and a high voltage in parallel, the fourth point is connected with a low voltage, the voltage level of the first connection point is low if the first point and the second point are shorted and the third point and the fourth point are shorted, the voltage level of the first connection point is high if the electrically coupling between the first point and the second point is open or the electrically coupling between the third point and the fourth point is open. 
     In one embodiment, the dual ramp means connects with a tip section. 
     In one embodiment, the circuit is placed at the edge of the first end of the second circuit board. 
     One aspect of the application is to provide a circuit switch, comprises: a first circuit board, a second circuit board, a third circuit board which are intact and sequentially parallel to each other, and a dual ramp means, wherein a first end of the first circuit board and a first end of the third circuit board contacts with the two ramps of the dual ramp means, respectively, a first end of the second circuit board does not contact with the dual ramp means, the first end of the second circuit board comprises a circuit, a second point of the circuit contacts with and electrically couples to a first point of the first circuit board. 
     In one embodiment, when the dual ramp means moves toward the second circuit board, the first circuit board and the third circuit board pressed by the dual ramp means and bent upward and downward, respectively, whereby the electrically coupling between the first point and the second point is open. 
     In one embodiment, the first point is connected with a first connection point and a high voltage, the second point is connected with a low voltage, the voltage level of the first connection point is low if the first point and the second point are shorted, the voltage level of the first connection point is high if the electrically coupling between the first point and the second point is open. 
     In one embodiment, the dual ramp means connects with a tip section. 
     In one embodiment, the circuit is placed at the edge of the first end of the second circuit board. 
     One aspect of the application is to provide a stylus, comprises: a control unit, a tip section; and a circuit switch, which comprises: a first circuit board, a second circuit board, a third circuit board which are intact and sequentially parallel to each other, and a dual ramp means, wherein a first end of the first circuit board and a first end of the third circuit board contact with the two ramps of the dual ramp means, respectively, a first end of the second circuit board does not contact with the dual ramp means, the first end of the second circuit board comprises a circuit, a second point and a third point of the circuit contacts with and electrically couples to a first point of the first circuit board and a fourth point of the third circuit board, respectively, wherein the first point connects with a first connection point of the control unit and a high voltage in parallel, the fourth point is connected with a low voltage, the voltage of the first connection port is low. 
     In one embodiment, when the dual ramp means moves toward the second circuit board, the first circuit board and the third circuit board pressed by the dual ramp means and bent upward and downward, respectively, whereby the electrically coupling between the first point and the second point is open and the electrically coupling between the third point and the fourth point is open, the voltage level of the first connection port is high. 
     In one embodiment, the control unit is waked up if the voltage level of the first connection port turns high from low. 
     One aspect of the application is to provide a stylus, comprises: a control unit, a tip section; and a circuit switch, which comprises: a first circuit board, a second circuit board, a third circuit board which are intact and sequentially parallel to each other, and a dual ramp means, wherein a first end of the first circuit board and a first end of the third circuit board contacts with the two ramps of the dual ramp means, respectively, a first end of the second circuit board does not contact with the dual ramp means, the first end of the second circuit board comprises a circuit, a second point of the circuit contacts with and electrically couples to a first point of the first circuit board, wherein the first point connects with a first connection point of the control unit and a high voltage in parallel, the second point is connected with a low voltage, the voltage of the first connection port is low. 
     In one embodiment, when the dual ramp means moves toward the second circuit board, the first circuit board and the third circuit board pressed by the dual ramp means and bent upward and downward, respectively, whereby the electrically coupling between the first point and the second point is open, the voltage level of the first connection port is high. 
     In one embodiment, the control unit is waked up if the voltage level of the first connection port turns high from low. 
     One aspect of the application is to provide a method for a transmitter, comprises: transmitting a first period electric signal during a first time period; and transmitting a second period electric signal during a second time period, wherein frequency group contained in the first period electric signal is different from frequency group contained in the second period electric signal. 
     One aspect of the application is to provide a transmitter, which is configured for transmitting a first period electric signal during a first time period; and transmitting a second period electric signal during a second time period, wherein frequency group contained in the first period electric signal is different from frequency group contained in the second period electric signal. 
     One aspect of the application is to provide a touch sensitive system, comprises a transmitter, a touch panel and a touch sensitive processing apparatus coupled to the touch panel, which is configured for detecting the transmitter according to a first period electric signal and a second period electric signal. The transmitter is configured for transmitting the first period electric signal during a first time period; and transmitting the second period electric signal during a second time period, wherein frequency group contained in the first period electric signal is different from frequency group contained in the second period electric signal. 
     In one embodiment, the frequency group contains one or more frequencies. 
     In one embodiment, the first time period is after a beacon signal detected by the transmitter. Alternatively, there exists a first delay time between the beacon signal detection and the first time period. 
     In one embodiment, there exists a second delay time between the first time period and the second time period. 
     In one embodiment, there exists a third delay time after the second time period. 
     In one embodiment, prior to the detection of the beacon signal, the transmitter detects an interference signal. Alternatively, the interference signal comprises signals which are coherent to the first period electric signal and the second electric signal. 
     Please refer to the Table 1, in one embodiment, if a tip section of the transmitter does not touch, a first signal source and a second signal source of the transmitter simultaneously transmit signals with the same frequency group. 
     Please refer to the Table 1, in one embodiment, if the tip section of the transmitter does not touch and a first switch of the transmitter is open, the first signal source and the second signal source simultaneously transmit signals with a first frequency group; if the tip section does not touch and the first switch is shorted, the first signal source and the second signal source simultaneously transmit signals with a second frequency group, the first frequency group is different to the second frequency group. 
     Please refer to the Table 1, in one embodiment, if the tip section of the transmitter does not touch and a second switch of the transmitter is open, the first signal source and the second signal source simultaneously transmit signals with the first frequency group; if the tip section does not touch and the second switch is shorted, the first signal source and the second signal source simultaneously transmit signals with a third frequency group, the first frequency group is different to the third frequency group. 
     Please refer to the Table 2, in one embodiment, if a tip section of the transmitter does touch, a first signal source and a second signal source of the transmitter transmit signals with different frequency groups during the second time period and the first time period. 
     Please refer to the Table 2, in one embodiment, if the tip section of the transmitter does touch and a first switch of the transmitter is open, the second signal source transmits signal with a first frequency group during the first time period; if a tip section of the transmitter does touch and the first switch of the transmitter is shorted, the second signal source transmits signal with a second frequency group during the first time period, the first frequency group is different to the second frequency group. 
     Please refer to the Table 2, in one embodiment, if the tip section of the transmitter does touch and a second switch of the transmitter is open, the first signal source transmits signal with a third frequency group during the second time period; if a tip section of the transmitter does touch and the second switch of the transmitter is shorted, the first signal source transmits signal with the second frequency group during the second time period, the third frequency group is different to the second frequency group. 
     In one embodiment, a ratio of a first signal strength M 1  transmitted by the first signal source during the second time period and a second signal strength M 2  transmitted by the second signal source during the first time period is corresponding to a pressure on the transmitter. 
     In one embodiment, a ring electrode transmits a zeroth period electric signal during a zeroth time period, the zeroth time period is after the transmitter detects the beacon signal. Alternatively, there exists a zeroth delay time between the detection of the beacon signal and the zeroth time period. 
     In one embodiment, the ring electrode does not transmit electric signal during the first time period and the second time period. 
     In one embodiment, frequency group contained in the zeroth period electric signal is different to frequency group contained the first period electric signal and the second period electric signal. 
     One aspect of the application is to provide a method for a transmitter, comprises: transmitting a first period electric signal during a first time period; and transmitting a second period electric signal during a second time period, wherein frequency group contained in the first period electric signal is as the same as frequency group contained in the second period electric signal. 
     One aspect of the application is to provide a transmitter, which is configured for transmitting a first period electric signal during a first time period; and transmitting a second period electric signal during a second time period, wherein frequency group contained in the first period electric signal is as the same as frequency group contained in the second period electric signal. 
     One aspect of the application is to provide a touch sensitive system, comprises a transmitter, a touch panel and a touch sensitive processing apparatus coupled to the touch panel, which is configured for detecting the transmitter according to a first period electric signal and a second period electric signal. The transmitter is configured for transmitting the first period electric signal during a first time period; and transmitting the second period electric signal during a second time period, wherein frequency group contained in the first period electric signal is as the same as frequency group contained in the second period electric signal. 
     In one embodiment, the frequency group contains one or more frequencies. 
     In one embodiment, the first time period is after a beacon signal detected by the transmitter. Alternatively, there exists a first delay time between the beacon signal detection and the first time period. 
     In one embodiment, there exists a second delay time between the first time period and the second time period. 
     In one embodiment, there exists a third delay time after the second time period. 
     In one embodiment, prior to the detection of the beacon signal, the transmitter detects an interference signal. Alternatively, the interference signal comprises signals which are coherent to the first time period electric signal and the second time period electric signal. 
     Please refer to the Table 3, in one embodiment, if a tip section of the transmitter does not touch, a first signal source and a second signal source of the transmitter simultaneously transmit signals with the same frequency group. 
     Please refer to the Table 3, in one embodiment, if the tip section of the transmitter does not touch and a first switch of the transmitter is open, the first signal source and the second signal source simultaneously transmit signals with a first frequency group; if the tip section does not touch and the first switch is shorted, the first signal source and the second signal source simultaneously transmit signals with a second frequency group, the first frequency group is different to the second frequency group. 
     Please refer to the Table 3, in one embodiment, if the tip section of the transmitter does not touch and a second switch of the transmitter is open, the first signal source and the second signal source simultaneously transmit signals with the first frequency group; if the tip section does not touch and the second switch is shorted, the first signal source and the second signal source simultaneously transmit signals with a third frequency group, the first frequency group is different to the third frequency group. 
     Please refer to the Table 4, in one embodiment, if a tip section of the transmitter does touch, a first signal source and a second signal source of the transmitter transmit signals with the same frequency groups during the second time period and the first time period, respectively. 
     Please refer to the Table 4, in one embodiment, if a tip section of the transmitter does touch and a first switch of the transmitter is open, the second signal source transmits signal with a first frequency group during the first time period; if a tip section of the transmitter does touch and the first switch of the transmitter is shorted, the second signal source transmits signal with a second frequency group during the first time period, the first frequency group is different to the second frequency group. 
     Please refer to the Table 4, in one embodiment, if the tip section of the transmitter does touch and a second switch of the transmitter is open, the first signal source transmits signal with a third frequency group during the second time period; if a tip section of the transmitter does touch and the second switch of the transmitter is shorted, the first signal source transmits signal with the second frequency group during the second time period, the third frequency group is different to the second frequency group. 
     In one embodiment, a ring electrode transmits a zeroth period electric signal during a zeroth time period, the zeroth time period is after the transmitter detects the beacon signal. Alternatively, there exists a zeroth delay time between the detection of the beacon signal and the zeroth time period. 
     In one embodiment, the ring electrode does not transmit electric signal during the first time period and the second time period. 
     In one embodiment, frequency group contained in the zeroth period electric signal is the same as frequency group contained the first period electric signal and the second period electric signal. 
     In one embodiment, a ratio of a first signal strength M 1  transmitted by the first signal source during the second time period and a second signal strength M 2  transmitted by the second signal source during the first time period is corresponding to a pressure on the transmitter. 
     One aspect of the application is to provide a method for detecting a transmitter, comprises: detecting a first period electric signal emitted from the transmitter during a first time period; and detecting a second period electric signal emitted from the transmitter from a second time period, wherein frequency group contained in the first period electric signal is different from frequency group contained in the second period electric signal. 
     One aspect of the application is to provide a touch sensitive processing apparatus for detecting a transmitter, coupled to a touch panel which comprises a plurality of first electrodes and a plurality of second electrodes as well as multiple sensing points located where the intersections, the touch sensitive processing apparatus is configured for detecting a first period electric signal emitted from the transmitter during a first time period; and detecting a second period electric signal emitted from the transmitter from a second time period, wherein frequency group contained in the first period electric signal is different from frequency group contained in the second period electric signal. 
     One aspect of the application is to provide a touch sensitive system comprises a transmitter, a touch panel, and a touch sensitive processing apparatus, coupled to the touch panel, configured for detecting a first period electric signal emitted from the transmitter during a first time period; and detecting a second period electric signal emitted from the transmitter from a second time period, wherein frequency group contained in the first period electric signal is different from frequency group contained in the second period electric signal. 
     In one embodiment, the frequency group contains one or more frequencies. 
     In one embodiment, the first time period is after a beacon signal detected by the transmitter. Alternatively, there exists a first delay time between the beacon signal detection and the first time period. 
     In one embodiment, there exists a second delay time between the first time period and the second time period. 
     In one embodiment, there exists a third delay time after the second time period. In another embodiment, other detection steps are still included after the second time period. 
     In one embodiment, prior to the detection of the beacon signal, the transmitter detects an interference signal. In one embodiment, an interference signal is detected after the first time period. In one embodiment, an interference signal is detected after the second time period. Alternatively, the interference signal comprises signals which are coherent to the first period electric signal and the second period electric signal. 
     Please refer to the Table 1, in one embodiment, if the transmitter simultaneously transmits signals with the same frequency group, it is determined that a tip section of the transmitter does not touch. 
     Please refer to the Table 1, in one embodiment, if the transmitter transmits signals with a first frequency group during a first time period, it is determined that the tip section does not touch and a first switch of the transmitter is open; if the transmitter transmits signals with a second frequency group during the first time period, it is determined that the tip section does not touch and the first switch of the transmitter is shorted, wherein the first frequency group is different to the second frequency group. 
     Please refer to the Table 1, in one embodiment, if the transmitter transmits signals with a first frequency group during a second time period, it is determined that the tip section does not touch and a second switch of the transmitter is open; if the transmitter transmits signals with a third frequency group during the second time period, it is determined that the tip section does not touch and the second switch of the transmitter is shorted, wherein the first frequency group is different to the third frequency group. 
     Please refer to the Table 2, in one embodiment, if the transmitter transmits signals with different frequency groups during the first time period and the second time period, it is determined that a tip section of the transmitter does touch. 
     Please refer to the Table 2, in one embodiment, if the transmitter transmits signal with a first frequency group during the first time period, it is determined that the tip section does touch and a first switch of the transmitter is open; if the transmitter transmits signal with a second frequency group during the first time period, it is determined that the tip section does touch and the first switch of the transmitter is shorted, wherein the first frequency group is different to the second frequency group. 
     Please refer to the Table 2, in one embodiment, if the transmitter transmits signal with a third frequency group during the second time period, it is determined that the tip section does touch and a second switch of the transmitter is open; if the transmitter transmits signal with a second frequency group during the second time period, it is determined that the tip section does touch and the second switch of the transmitter is shorted, wherein the third frequency group is different to the second frequency group. 
     In one embodiment, a ratio of a first signal strength M 1  transmitted by the first signal source during the second time period and a second signal strength M 2  transmitted by the second signal source during the first time period is calculated; and a pressure on the transmitter according to the ratio is calculated. 
     In one embodiment, detecting a zeroth period electric signal transmitted by the transmitter during a zeroth time period, the zeroth time period is after the transmitter detects the beacon signal. Alternatively, there exists a zeroth delay time between the detection of the beacon signal and the zeroth time period. 
     In one embodiment, frequency group contained in the zeroth period electric signal is different to frequency group contained in the first period electric signal and the second period electric signal. 
     One aspect of the application is to provide a method for detecting a transmitter, comprises: detecting a first period electric signal emitted from the transmitter during a first time period; and detecting a second period electric signal emitted from the transmitter from a second time period, wherein frequency group contained in the first period electric signal is as the same as frequency group contained in the second period electric signal. 
     One aspect of the application is to provide a touch sensitive processing apparatus for detecting a transmitter, coupled to a touch panel which comprises a plurality of first electrodes and a plurality of second electrodes as well as multiple sensing points located where the intersections, the touch sensitive processing apparatus is configured for detecting a first period electric signal emitted from the transmitter during a first time period; and detecting a second period electric signal emitted from the transmitter from a second time period, wherein frequency group contained in the first period electric signal is as the same as frequency group contained in the second period electric signal. 
     One aspect of the application is to provide a touch sensitive system comprises a transmitter, a touch panel, and a touch sensitive processing apparatus, coupled to the touch panel which comprises a plurality of first electrodes and a plurality of second electrodes as well as multiple sensing points located where the intersections, the touch sensitive processing apparatus is configured for detecting a first period electric signal emitted from the transmitter during a first time period; and detecting a second period electric signal emitted from the transmitter from a second time period, wherein frequency group contained in the first period electric signal is as the same as frequency group contained in the second period electric signal. 
     In one embodiment, the frequency group contains one or more frequencies. 
     In one embodiment, the first time period is after a beacon signal detected by the transmitter. Alternatively, there exists a first delay time between the beacon signal detection and the first time period. 
     In one embodiment, there exists a second delay time between the first time period and the second time period. 
     In one embodiment, there exists a third delay time after the second time period. In another embodiment, other detection steps are still included after the second time period. 
     In one embodiment, prior to the detection of the beacon signal, the transmitter detects an interference signal. In one embodiment, an interference signal is detected after the first time period. In one embodiment, an interference signal is detected after the second time period. Alternatively, the interference signal comprises signals which are coherent to the first period electric signal and the second period electric signal. 
     Please refer to the Table 3, in one embodiment, if the first period electric signals with the same frequency group and the second period electric signals with the same frequency group, it is determined that a tip section of the transmitter does not touch. 
     Please refer to the Table 3, in one embodiment, if the transmitter transmits signals with a first frequency group, it is determined that the tip section does not touch and a first switch of the transmitter is open; if the transmitter transmits signals with a second frequency group, it is determined that the tip section does not touch and the first switch of the transmitter is shorted, wherein the first frequency group is different to the second frequency group. 
     Please refer to the Table 3, in one embodiment, if the transmitter transmits signals with a first frequency group, it is determined that the tip section does not touch and a second switch of the transmitter is open; if the transmitter transmits signals with a third frequency group, it is determined that the tip section does not touch and the second switch of the transmitter is shorted, wherein the first frequency group is different to the third frequency group. 
     Please refer to the Table 4, in one embodiment, if the first period electric signals with the same frequency group and the second period electric signals with the same frequency group and a ratio of a signal strength M 1  of the first period electric signal and a signal strength M 2  of the second period electric signal does not fall into a first range, it is determined that a tip section of the transmitter does not touch. 
     Please refer to the Table 4, in one embodiment, if the transmitter transmits signal with a first frequency group during the first time period and the ratio does not fall into a first range, it is determined that the tip section does touch and a first switch of the transmitter is open; if the transmitter transmits signal with a second frequency group during the first time period and the ratio does not fall into the first range, it is determined that the tip section does touch and the first switch of the transmitter is shorted, wherein the first frequency group is different to the second frequency group. 
     Please refer to the Table 4, in one embodiment, if the transmitter transmits signal with a third frequency group during the second time period and the ratio does not fall into a first range, it is determined that the tip section does touch and a second switch of the transmitter is open; if the transmitter transmits signal with a second frequency group during the second time period and the ratio does not fall into the first range, it is determined that the tip section does touch and the second switch of the transmitter is shorted, wherein the third frequency group is different to the second frequency group. 
     In one embodiment, a ratio of a first signal strength M 1  transmitted by the first signal source during the second time period and a second signal strength M 2  transmitted by the second signal source during the first time period is calculated; and a pressure on the transmitter according to the ratio is calculated. 
     In one embodiment, detecting a zeroth period electric signal transmitted by the transmitter during a zeroth time period, the zeroth time period is after the transmitter detects the beacon signal. Alternatively, there exists a zeroth delay time between the detection of the beacon signal and the zeroth time period. 
     In one embodiment, frequency group contained in the zeroth period electric signal is as the same as frequency group contained the first period electric signal and the second period electric signal. 
     One aspect of the present application is to provide a transmitter, comprises: a tip section and a ring electrode surrounding the tip section, wherein the tip section is not electrically coupling to the ring electrode. 
     In one embodiment, the ring electrode comprises multiple disconnected electrodes. 
     In one embodiment, the transmitter transmits electric signals via the ring electrode and the tip section during a zeroth time period. In another embodiment, the transmitter transmits electric signals via the tip section during a first time period. Alternatively, the first time period is after the zeroth time period. 
     In one embodiment, electric signals emitted from the ring electrode and the tip section contains the same frequency group. Alternatively, electric signal emitted from the ring electrode contains frequency group different to the frequency group contained in the electric signal emitted from the tip electrode. 
     One aspect of the present application is to provide a method for detecting a position of a transmitter, wherein the transmitter comprises a tip section and a ring electrode surrounding the tip section, wherein the tip section is not electrically coupling to the ring electrode, the method comprises detecting electric signals emitted from the ring electrode and the tip section during a zeroth time period; and detecting electric signals emitted from the tip section during a first time period. 
     One aspect of the present application is to provide a touch sensitive processing apparatus for detecting a position of a transmitter, wherein the transmitter comprises a tip section and a ring electrode surrounding the tip section, wherein the tip section is not electrically coupling to the ring electrode, the touch sensitive processing apparatus is coupled to a touch panel which comprises a plurality of first electrodes and a plurality of second electrodes and multiple sensing points located where the intersections, the touch sensitive processing apparatus is configured for detecting electric signals emitted from the ring electrode and the tip section during a zeroth time period; and detecting electric signals emitted from the tip section during a first time period. 
     One aspect of the present application is to provide a touch sensitive system, comprises a transmitter, a touch panel, and a touch sensitive processing apparatus coupled to the touch panel. The transmitter comprises a tip section and a ring electrode surrounding the tip section, wherein the tip section is not electrically coupling to the ring electrode. The touch sensitive processing apparatus is coupled to a touch panel which comprises a plurality of first electrodes and a plurality of second electrodes and multiple sensing points located where the intersections, the touch sensitive processing apparatus is configured for detecting electric signals emitted from the ring electrode and the tip section during a zeroth time period; and detecting electric signals emitted from the tip section during a first time period. 
     In one embodiment, electric signals emitted from the ring electrode and the tip section contain the same frequency group. Alternatively, electric signals emitted from the ring electrode contain frequency group different to the frequency group contained in the electric signals emitted from the tip electrode. 
     In one embodiments, the first time period is after the zeroth time period. 
     In one embodiment, the method further comprises calculating a first centroid position of the transmitter according to the electric signal detected during the zeroth time period. Alternatively, the method further comprises calculating a second centroid position of the transmitter according to the electric signal detected during the first time period. 
     In one embodiment, the method further comprises calculating a surface position where the transmitter touches the touch panel according to the first centroid position and the second centroid position, wherein the surface position is the position where the axis of the tip section projecting to a surface layer of the touch panel. 
     In one embodiment, the method further comprises calculating a display position where the transmitter touches the touch panel according to the first centroid position and the second centroid position, wherein the display position is the position where the axis of the tip section projecting to a display layer of the touch panel. 
     In one embodiment, the method further comprises calculating an inclination angle of the transmitter touches the touch panel according to the first centroid position and the second centroid position. 
     One aspect of the present application is to provide a method for calculating a surface position where a transmitter touches a touch panel, the method comprises: receiving a first centroid position of the transmitter, wherein the first centroid is calculated according to electric signals emitted from a ring electrode and a tip section of the transmitter, receiving a second centroid position of the transmitter, wherein the second centroid is calculated according to electric signals emitted from the tip section of the transmitter; and calculating the surface position where the transmitter touches the touch panel according to the first centroid position and the second centroid position, wherein the surface position is the position where the axis of the tip section projecting to a surface layer of the touch panel. 
     One aspect of the present application is to provide a method for calculating a display position where a transmitter touches a touch panel, the method comprises: receiving a first centroid position of the transmitter, wherein the first centroid position is calculated according to electric signals emitted from a ring electrode and a tip section of the transmitter, receiving a second centroid position of the transmitter, wherein the second centroid position is calculated according to electric signals emitted from the a tip section of the transmitter; and calculating the display position where the transmitter touches the touch panel according to the first centroid position and the second centroid position, wherein the display position is the position where the axis of the tip section projecting to a display layer of the touch panel. 
     One aspect of the present application is to provide a method for calculating an inclination angle of a transmitter touches a touch panel, the method comprises: receiving a first centroid position of the transmitter, wherein the first centroid position is calculated according to electric signals emitted from a ring electrode and a tip section of the transmitter, receiving a second centroid position of the transmitter, wherein the second centroid position is calculated according to electric signals emitted from the a tip section of the transmitter; and calculating the inclination angle according to the first centroid position and the second centroid position. 
     In one embodiment, the first centroid position is calculated during a zeroth time period. In one embodiment, the second centroid position is calculated during a first time period. Alternatively, the first time period is after the zeroth time period. In one embodiment, electric signal emitted from the ring electrode contains frequency group different to the frequency group contained in the electric signal emitted from the tip electrode. 
     One aspect of the present application is to provide a display method, comprises: receiving a position of a transmitter; receiving an inclination angle of the transmitter; determining a display area according to the position and the inclination angle. 
     In one embodiment, the position is one of the followings: a first centroid position, a second centroid position, a surface position; and a display position. The first centroid position is calculated according to electric signals emitted from a ring electrode and a tip section of the transmitter. The second centroid position is calculated according to electric signals emitted from the tip section of the transmitter. The surface position is the position where the axis of the tip section projecting to a surface layer of the touch panel. The display position is the position where the axis of the tip section projecting to a display layer of the touch panel. In one embodiment, electric signal emitted from the ring electrode contains frequency group different to the frequency group contained in the electric signal emitted from the tip electrode. 
     In one embodiment, the display area comprises an ellipse. Alternatively, the position is located one of the followings: a center of the ellipse, one of two focal points of the ellipse; and one of intersections of the semi-major axis and the ellipse. In one embodiment, the semi-major axis is corresponding to the direction of the inclination angle. 
     In one embodiment, the display area comprises a tear drop shape. Alternatively, the position is located one of the followings: a center of the tear drop shape, a top of the tear drop shape; and an end of the tear drop shape. In one embodiment, the direction of the tear drop shape is corresponding to the direction of the inclination angle. 
     In one embodiment, the direction of the display area is corresponding to the direction of the inclination angle. Alternatively, the size of the display area is corresponding to the inclination angle. Alternatively, the color of the display area is corresponding to one of the followings: the inclination angle; and the direction of the inclination angle. 
     In one embodiment, it further comprises receiving a pressure of the transmitter; the size of the display area is corresponding to the pressure. 
     One aspect of the present application is to provide a method for controlling the transmitter, comprises: transmitting a first electric signal with a first signal strength if a force sensor of the transmitter does not sense any force; transmitting a second electric signal with a second signal strength if the force sensor does sense force, wherein the first signal strength is larger than the second signal strength. 
     In one embodiment, the force sensor comprises a tip section of the transmitter. 
     In one embodiment, the transmitter further comprises a ring electrode. The first electric signal is transmitted via the tip section and the ring electrode, the second electric signal is transmitted via the tip section. 
     One aspect of the application is to provide a transmitter, comprises a force sensor and a control unit, which is configured to transmit a first electric signal with a first signal strength if a force sensor of the transmitter does not sense any force; transmitting a second electric signal with a second signal strength if the force sensor does sense force, wherein the first signal strength is larger than the second signal strength. 
     Referring to  FIG.  30   , a block diagram of a transmitter  110  in accordance with an embodiment of the present invention is illustrated. The transmitter  110  includes a first sensor  3010 , a second sensor  3020 , a third sensor  3030 , and a processing module  3090  connecting to the sensors  3010 ,  3020 , and  3030 . The transmitter  110  may further include a tip section  230  and a ring electrode  550  surrounding the tip section  230 . In one embodiment, the first sensor  3010  senses a pressure value on the tip section  230 , transferring the pressure value into a digital sensing value, and then transmits the digital sensing value to the processing module  3090 . The second and the third sensors  3020  and  3030  could transmit the digital sensing value to the processing module  3090  as well. The processing module  3090  emits each electric signal to the tip section and/or the ring electrode to show at least one or all part of the digital sensing value of each sensor. 
     Referring to  FIG.  9 A  to  FIG.  9 I , and  FIG.  30   , one of the features of the present invention is to provide a transmitter including a first sensor and a processing module connecting to the first sensor. Wherein, the processing module is used to emit a first electric signal during a first time period, and the first electric signal is used to represent at least one part of a digital sensing value of the first sensor. 
     In one embodiment, the digital sensing value is a pressure digital value, which the first sensor senses the pressure on the tip section of the transmitter. Alternatively, the processing module emits the first electric signal by the tip section. 
     In one embodiment, the first electric signal includes a transmitted state and a non-transmitted state. 
     In one embodiment, the first electric signal is used to represent a first digital of the digital sensing value in number system based on N, where N is bigger than or equal to 2. In another embodiment, the first electric signal includes at least N−1 state value. In still another embodiment, the first electric signal further includes any or any combination of the redundancy code, the error correcting code, and the check code of the state value thereof. 
     In one embodiment, the transmitting time length of the first electric signal relates to the first digital&#39;s value and a unit time length. 
     In one embodiment, the pulse-repeating frequency of the first electric signal relates to the first digital&#39;s value. 
     In one embodiment, the processing module is used to emits a second electric signal, the second electric signal is used to represent a second digital of the digital sensing value in number system based on M, where M is bigger than or equal to 2. In another embodiment, M is not equal to N. In another embodiment, the second electric signal includes at least M−1 state value. Wherein, the second electric signal further includes any or any combination of the redundancy code, the error correcting code, and the check code of the state value thereof. 
     In one embodiment, the transmitting time length of the second electric signal relates to the second digital&#39;s value and a unit time length, an interval between the first and the second time periods does not transmit the electric signal. 
     In one embodiment, the pulse-repeating frequency of the second electric signal relates to the second digital&#39;s value. In another embodiment, the first time length is equal to the second time length. 
     In one embodiment, the transmitter further includes a second sensor, and wherein the processing module is used to emits a third electric signal in a third time period, the third electric signal is used to represent the digital sensing value of the second sensor. In another embodiment, the transmitter further includes a third sensor, and the third electric signal is further to represent the digital sensing value of the third sensor. In another embodiment, the third time period is after the transmitter receiving a beacon signal, the first time period is after the third time period. In still another embodiment, the transmitter further includes a ring electrode surrounding the tip section, the third electric signal is emitted by the tip section or the ring electrode or the combination of them. 
     Referring to  FIG.  31   , a flow chart of controlling method for a transmitter in accordance with an embodiment of the present invention is illustrated. This controlling method may adapt to the transmitter shown in  FIG.  30   . It is noted that the steps  3110 ,  3120 , and  3130  have no relationship in sequence, they can be performed in any order. 
     Referring to  FIG.  9 A  to  FIG.  9 I ,  FIG.  30   , and  FIG.  31   , one of the features of the present invention is to provide a controlling method for a transmitter. The transmitter included a first sensor. The controlling method includes step  3110 , emitting a first electric signal during a first time period, and the first electric signal is used to represent at least one part of a digital sensing value of the first sensor. 
     In one embodiment, the controlling method further includes utilizing the first sensor to sense a pressure digital value, which is the pressure on the tip section of the transmitter sensed by the first sensor, so as to get a digital sensing value of the first sensor. Alternatively, the controlling method further includes emitting the first electric signal by the tip section. 
     In one embodiment, the first electric signal includes a transmitted state and a non-transmitted state. 
     In one embodiment, the first electric signal is used to represent a first digital of the digital sensing value in number system based on N, where N is bigger than or equal to 2 (step  3310 ). In another embodiment, the first electric signal includes at least N−1 state value. In still another embodiment, the first electric signal further includes any or any combination of the redundancy code, the error correcting code, and the check code of the state value thereof. 
     In one embodiment, the transmitting time length of the first electric signal relates to the first digital&#39;s value and a unit time length. 
     In one embodiment, the pulse-repeating frequency of the first electric signal relates to the first digital&#39;s value. 
     In one embodiment, the controlling method further includes emitting a second electric signal in a second time period, the second electric signal is used to represent a second digital of the digital sensing value in number system based on M, where M is bigger than or equal to 2 (step  3120 ). In another embodiment, M is not equal to N. In another embodiment, the second electric signal includes at least M−1 state value. Wherein, the second electric signal further includes any or any combination of the redundancy code, the error correcting code, and the check code of the state value thereof. 
     In one embodiment, the transmitting time length of the second electric signal relates to the second digital&#39;s value and a unit time length, an interval between the first and the second time periods does not transmit the electric signal. 
     In one embodiment, the pulse-repeating frequency of the second electric signal relates to the second digital&#39;s value. In another embodiment, the first time length is equal to the second time length. 
     In one embodiment, the transmitter further includes a second sensor, and wherein the controlling method further includes emitting a third electric signal in a third time period, the third electric signal is used to represent the digital sensing value of the second sensor (step  3130 ). In another embodiment, the transmitter further includes a third sensor, and the third electric signal is further to represent the digital sensing value of the third sensor. In another embodiment, the third time period is after the transmitter receiving a beacon signal, the first time period is after the third time period. In still another embodiment, the transmitter further includes a ring electrode surrounding the tip section, the third electric signal is emitted by the tip section or the ring electrode or the combination of them. 
     Referring to  FIG.  32   , a block diagram of a touch sensitive processing apparatus in accordance with an embodiment of the present invention is illustrated. The touch sensitive processing apparatus could be the touch sensitive processing apparatus  130  shown in  FIG.  1   , which is used to connect multiple the first and the second electrodes  121  and  122  of the touch panel  120 , and is used to detect the state of the sensor of a transmitter  110  approaching or touching the touch panel  120 . The touch sensitive processing apparatus includes a signal detecting module and a processing module. 
     Referring to  FIG.  9 A  to  FIG.  9 F , and  FIG.  32   , one of the features of the present invention is to provide a touch sensitive processing apparatus connecting to multiple the first and the second electrodes of a touch panel, detecting the state of the sensor of a transmitter approaching or touching the touch panel, and includes a signal detecting module  3210  used to detect a first electric signal received by one of the multiple first and second electrodes in a first time period and a processing module  3220  used to receive the first electric signal from the signal detecting module to determine a first digital value based on the first electric signal so as to denote at least one part of the digital sensing value of a first sensor of the transmitter. 
     In one embodiment, the touch sensitive processing apparatus further includes a beacon signal transmitting module used to transmit a beacon signal by the multiple first and second electrodes. In another embodiment, the transmitting time of the beacon signal is earlier than the first time period. 
     In one embodiment, the first digital value determined by the processing module is used to represent a first digital of the first sensor&#39;s digital sensing value in number system based on N, where N is bigger than or equal to 2. In another embodiment, the multiple first state values include at least N−1 state value. In still another embodiment, the multiple first state values further include any or any combination of the redundancy code, the error correcting code, and the check code. 
     In one embodiment, the transmitting time length of the first electric signal relates to the first digital&#39;s value and a unit time length. 
     In one embodiment, the pulse-repeating frequency of the first electric signal relates to the first digital&#39;s value. 
     In one embodiment, the signal detecting module is further used to detect a second electric signal received by one of the multiple first and second electrodes in a second time period, and the processing module is further used to receive the second electric signal from the signal detecting module to determine a second digital value based on the second electric signal so as to represent a second digital of the first sensor&#39;s digital sensing value of the transmitter in number system based on M, where M is bigger than or equal to 2. In another embodiment, M is not equal to N. In another embodiment, the multiple second state values include at least M−1 state value. In another embodiment, the multiple state values further include any or any combination of the redundancy code, the error correcting code, and the check code. 
     In one embodiment, the transmitting time length of the second electric signal relates to the second digital&#39;s value and a unit time length, an interval between the first and the second time periods does not transmit the electric signal. 
     In one embodiment, the pulse-repeating frequency of the second electric signal relates to the second digital&#39;s value. In another embodiment, the first time length is equal to the second time length. 
     In one embodiment, the signal detecting module is further used to detect a third electric signal received by one of the multiple first and second electrodes in a third time period, and the processing module is further used to receive the third electric signal from the signal detecting module to determine a third digital value based on the third electric signal so as to represent a second sensor&#39;s digital sensing value of the transmitter. In another embodiment, the third digital value is further used to represent a third sensor&#39;s digital sensing value of the transmitter. 
     In one embodiment, the signal detecting module includes a filter used to filter out the noise of frequency unintended to receive, an integrator used to sample the filtered signal, and a comparator used to compare the sampled signal whether bigger than a predefined value, if yes, it means the electric signal transmitted by the transmitter is detected. In one embodiment, the integrator includes dual-slope integrator. 
     In one embodiment, the signal detecting module includes a demodulator used to multiply the sampled signal and the frequency signal the demodulator intends to receive and then sum them up. When the sum is bigger than a predetermined value, it means the electric signal transmitted by the transmitter is detected. 
     Referring to  FIG.  33   , a flow chart of a method for detecting the status of a transmitter in accordance with an embodiment of the present invention is illustrated. This detecting method could be adapted to the touch sensitive processing apparatus shown in  FIG.  32   . It is noted that these steps could be performed in order except for specially required relationship. 
     Referring to  FIG.  9 A  to  FIG.  9 F ,  FIG.  32   , and  FIG.  33   , one of the features of the present invention is to provide a method for detecting the status of a transmitter. The method includes detecting a first electric signal received by one of multiple first and second electrodes of a touch panel in a first time period (step  3310 ), and determining a first digital value based on the first electric signal so as to represent at least one part of digital sensing value of a first sensor of the transmitter (step  3320 ). 
     In one embodiment, the detecting method further includes transmitting a beacon signal by the multiple first and second electrodes. In another embodiment, the transmitting time of the beacon signal is earlier than the first time period. 
     In one embodiment, the first digital value is used to represent a first digital of the first sensor&#39;s digital sensing value in number system based on N, where N is bigger than or equal to 2. In another embodiment, the multiple first state values include at least N−1 state value. In still another embodiment, the multiple first state values further include any or any combination of the redundancy code, the error correcting code, and the check code. 
     In one embodiment, the transmitting time length of the first electric signal relates to the first digital&#39;s value and a unit time length. 
     In one embodiment, the pulse-repeating frequency of the first electric signal relates to the first digital&#39;s value. 
     In one embodiment, the detecting method further includes detecting a second electric signal received by one of the multiple first and second electrodes in a second time period (step  3330 ), and determining a second digital value based on the second electric signal so as to represent a second digital of the first sensor&#39;s digital sensing value of the transmitter in number system based on M (step  3340 ), where M is bigger than or equal to 2. In another embodiment, M is not equal to N. In another embodiment, the multiple second state values include at least M−1 state value. In another embodiment, the multiple state values further include any or any combination of the redundancy code, the error correcting code, and the check code. 
     In one embodiment, the transmitting time length of the second electric signal relates to the second digital&#39;s value and a unit time length, an interval between the first and the second time periods does not transmit the electric signal. 
     In one embodiment, the pulse-repeating frequency of the second electric signal relates to the second digital&#39;s value. In another embodiment, the first time length is equal to the second time length. 
     In one embodiment, the detecting method further includes detecting a third electric signal received by one of the multiple first and second electrodes in a third time period (step  3350 ), and determining a third digital value based on the third electric signal so as to represent a second sensor&#39;s digital sensing value of the transmitter (step  3360 ). In another embodiment, the third digital value is further used to represent a third sensor&#39;s digital sensing value of the transmitter. 
     In one embodiment, the detecting method further includes a filtering step used to filter out the noise of unintended to receive frequency, an integrating step used to sample the filtered signal, and a comparing step used to compare the sampled signal whether bigger than a predefined value, if yes, it means the electric signal transmitted by the transmitter is detected. In one embodiment, the integrating step includes using a dual-slope integrator. 
     In one embodiment, the detecting method includes multiplying the sampled signal and the intending to receive frequency signal and then summing them up. When the sum is bigger than a predetermined value, it means the electric signal transmitted by the transmitter is detected. 
     Referring to  FIG.  1   ,  FIG.  9 A  to  FIG.  9 I ,  FIG.  30   , and  FIG.  32   , one of the features of the present invention is to provide a touch sensitive system including a transmitter, a touch panel, and a touch sensitive processing apparatus connecting to multiple first and second electrodes of the touch panel. The transmitter includes a first sensor, and a transmitter processing module connecting to the first sensor, wherein the transmitter processing module is used to emit a first electric signal in a first time period, and the first electric signal is used to represent at least one part of digital sensing value of the first sensor. The touch sensitive processing apparatus includes a signal detecting module used to detect the first electric signal received by one of the multiple first and second electrodes in the first time period, and a touch sensitive processing apparatus processing module used to receive the first electric signal from the signal detecting module to determine a first digital value based on the first electric signal so as to denote at least one part of the digital sensing value of the first sensor. 
     Please refer to  FIG.  1    and  FIG.  34 A  to  FIG.  34 B . One of the features of the present invention is to provide a transmitter used to receive a beacon signal from a touch panel and relatively emitting an electric signal with a first frequency to the touch panel such that a touch sensitive processing apparatus connecting to the touch panel know a position the transmitter corresponding to the touch panel. Wherein, when the transmitter determines the beacon signal with a first beacon signal frequency being interfered, it becomes to receive the beacon signal with a second beacon signal frequency and relatively emits the electric signal with the first frequency to the touch panel. 
     In one embodiment, when the transmitter determines the beacon signal with the second beacon signal frequency being interfered, it becomes to receive the beacon signal with a specify beacon signal frequency and relatively emits the electric signal with the second frequency to the touch panel. 
     One of the features of the present invention is to provide a controlling method of the transmitter including receiving a beacon signal from a touch panel, and relatively emitting an electric signal with a first frequency to the touch panel so as to let a touch sensitive processing apparatus connecting to the touch panel know a position the transmitter corresponding to the touch panel. Wherein, when the transmitter determines the beacon signal with a first beacon signal frequency being interfered, it becomes to receive the beacon signal with a second beacon signal frequency and relatively emits the electric signal with the first frequency to the touch panel. 
     In one embodiment, the controlling method further includes when determining the beacon signal with the second beacon signal frequency being interfered, turning to receive the beacon signal with a specify beacon signal frequency and relatively emitting the electric signal with the second frequency to the touch panel. 
     One of the features of the present invention is to provide a touch sensitive processing apparatus used to connect to a touch panel to emit a beacon signal with a first beacon signal frequency to a transmitter and through the touch panel to receive an electric signal with a first frequency emitted by the transmitter so as to know a position the transmitter corresponding to the touch panel. Wherein, when the touch sensitive processing apparatus determines the electric signal with a first frequency being interfered, it further emits the beacon signal with a specify beacon signal frequency and relatively receives the electric signal with a second frequency. 
     In one embodiment, the controlling method further includes that when the touch sensitive processing apparatus does not receive the electric signal with the first frequency, it turns to emit the beacon signal with a second beacon signal frequency to the transmitter. 
     One of the features of the present invention is to provide a controlling method for a touch sensitive processing apparatus. The controlling method includes emitting a beacon signal with a first beacon signal frequency by a touch panel to a transmitter, and receiving an electric signal with a first frequency emitted by the transmitter through the touch panel so as to know a position the transmitter corresponding to the touch panel. Wherein, when the touch sensitive processing apparatus determines the electric signal with the first frequency being interfered, it further emits the beacon signal with a specify beacon signal frequency and relatively receives the electric signal with a second frequency. 
     In one embodiment, the controlling method further includes that when the touch panel does not receive the electric signal with the first frequency, it turns to emit the beacon signal with a second beacon signal frequency to the transmitter. 
     Please refer to  FIG.  1    and  FIG.  34 A  to  FIG.  34 D . One of the features of the present invention is to provide a transmitter used to receive a beacon signal from a touch panel and relatively emitting an electric signal to the touch panel such that a touch sensitive processing apparatus connecting to the touch panel know a position the transmitter corresponding to the touch panel. Wherein, the transmitter is further used to actively scan the frequencies of the beacon signal and the electric signal that may be interfered and selects a set of non-interfered frequency of the beacon signal and the electric signal based on an order. 
     In one embodiment, the transmitter is further used to emit the interfered signal of interfered frequency acquired by actively scanning. 
     In one embodiment, when the transmitter determines the beacon signal with a first beacon signal frequency being interfered, it becomes to receive the beacon signal with a second beacon signal frequency and relatively emits the electric signal with the first frequency to the touch panel. In another embodiment, when the transmitter determines the beacon signal with the second beacon signal frequency being interfered, it turns to receive the beacon signal with a specify beacon signal frequency and relatively emits the electric signal with a second frequency to the touch panel. 
     One of the features of the present invention is to provide a controlling method for a transmitter. The controlling method includes receiving a beacon signal from a touch panel, relatively emitting an electric signal with a first frequency to the touch panel such that a touch sensitive processing apparatus connecting to the touch panel knows a position the transmitter corresponding to the touch panel, and actively scanning the frequencies of the beacon signal and the electric signal that may be interfered and selecting a set of non-interfered frequency of the beacon signal and the electric signal based on an order. 
     In one embodiment, the controlling method further includes emitting the interfered signal of interfered frequency acquired by actively scanning. 
     In one embodiment, the controlling method further includes that when the transmitter determines the beacon signal with a first beacon signal frequency being interfered, it becomes to receive the beacon signal with a second beacon signal frequency and relatively emits the electric signal with the first frequency to the touch panel. In another embodiment, the controlling method further includes that when the transmitter determines the beacon signal with the second beacon signal frequency being interfered, it turns to receive the beacon signal with a specify beacon signal frequency and relatively emits the electric signal with a second frequency to the touch panel. 
     One of the features of the present invention is to provide a touch sensitive processing apparatus used to connect to a touch panel to emit a beacon signal to a transmitter and receive an electric signal emitted by the transmitter through the touch panel so as to know a position the transmitter corresponding to the touch panel. Wherein, the touch sensitive processing apparatus is further used to actively scan the frequencies of the beacon signal and the electric signal that may be interfered and select a set of non-interfered frequency of the beacon signal and the electric signal based on an order. 
     In one embodiment, the touch sensitive processing apparatus is further used to emit the interfered signal of interfered frequency acquired by actively scanning. 
     In one embodiment, when the touch sensitive processing apparatus determines the electric signal with the first frequency being interfered, it further emits the beacon signal with a specify beacon signal frequency and relatively receives the electric signal with a second frequency. In another embodiment, when the touch sensitive processing apparatus does not receive the electric signal with the first frequency, it turns to emit the beacon signal with a second beacon signal frequency to the transmitter. 
     One of the features of the present invention is to provide a controlling method for a touch sensitive processing apparatus. The controlling method includes emitting a beacon signal to a transmitter through a touch panel, receiving an electric signal emitted by the transmitter through the touch panel so as to know a position the transmitter corresponding to the touch panel, and actively scanning the frequencies of the beacon signal and the electric signal that may be interfered and selecting a set of non-interfered frequency of the beacon signal and the electric signal based on an order. 
     In one embodiment, the controlling method further includes emitting the interfered signal of interfered frequency acquired by actively scanning. 
     In one embodiment, the controlling method further includes that when the touch sensitive processing apparatus determines the electric signal with the first frequency being interfered, it further emits the beacon signal with a specify beacon signal frequency and relatively receives the electric signal with a second frequency. In another embodiment, the controlling method further includes that when the touch sensitive processing apparatus does not receive the electric signal with the first frequency, it turns to emit the beacon signal with a second beacon signal frequency to the transmitter. 
     One of the features of the present invention is to provide a touch sensitive system including a transmitter, a touch panel, and a touch sensitive processing apparatus connecting to the touch panel. Wherein, the transmitter is used to receive a beacon signal from the touch panel and relatively emit an electric signal with a first frequency to the touch panel such that the touch sensitive processing apparatus knows a position the transmitter corresponding to the touch panel. Wherein, when the transmitter determines the beacon signal with a first beacon signal frequency being interfered, it becomes to receive the beacon signal with a second beacon signal frequency and relatively emits the electric signal with the first frequency to the touch panel. 
     In one embodiment, when the transmitter determines the beacon signal with the second beacon signal frequency being interfered, it turns to receive the beacon signal with a specify beacon signal frequency and relatively emits the electric signal with a second frequency to the touch panel. 
     In one embodiment, when the touch sensitive processing apparatus determines the electric signal with the first frequency being interfered, it further emits the beacon signal with a specify beacon signal frequency and relatively receives the electric signal with a second frequency. In another embodiment, when the touch sensitive processing apparatus does not receive the electric signal with the first frequency, it turns to emit the beacon signal with a second beacon signal frequency to the transmitter. 
     In one embodiment, the touch sensitive processing apparatus is further used to actively scan the frequencies of the beacon signal and the electric signal that may be interfered and select a set of non-interfered frequency of the beacon signal and the electric signal based on an order. In another embodiment, the touch sensitive processing apparatus is further used to emit the interfered signal of interfered frequency acquired by actively scanning. 
     One of the features of the present invention is to provide a touch sensitive system including a transmitter, a touch panel, and a touch sensitive processing apparatus connecting to the touch panel. The touch sensitive processing apparatus is used to emit a beacon signal with a first beacon signal frequency to the transmitter and through the touch panel to receive an electric signal with a first frequency emitted by the transmitter so as to know a position the transmitter corresponding to the touch panel. Wherein, when the touch sensitive processing apparatus determines the electric signal with a first frequency being interfered, it further emits the beacon signal with a specify beacon signal frequency and relatively receives the electric signal with a second frequency. 
     In one embodiment, when the touch sensitive processing apparatus does not receive the electric signal with the first frequency, it turns to emit the beacon signal with a second beacon signal frequency to the transmitter. 
     In one embodiment, when the transmitter determines the beacon signal with a first beacon signal frequency being interfered, it becomes to receive the beacon signal with a second beacon signal frequency and relatively emits the electric signal with the first frequency to the touch panel. In another embodiment, when the transmitter determines the beacon signal with the second beacon signal frequency being interfered, it turns to receive the beacon signal with a specify beacon signal frequency and relatively emits the electric signal with a second frequency to the touch panel. 
     In one embodiment, the transmitter is further used to actively scan the frequencies of the beacon signal and the electric signal that may be interfered and select a set of non-interfered frequency of the beacon signal and the electric signal based on an order. 
     One of the features of the present invention is to provide a touch sensitive system including a transmitter, a touch panel, and a touch sensitive processing apparatus connecting to the touch panel. Wherein, the transmitter is used to receive a beacon signal from the touch panel and relatively emit an electric signal with a first frequency to the touch panel such that the touch sensitive processing apparatus knows a position the transmitter corresponding to the touch panel. Wherein, the transmitter is further used to actively scan the frequencies of the beacon signal and the electric signal that may be interfered and select a set of non-interfered frequency of the beacon signal and the electric signal based on an order. Wherein, the touch sensitive processing apparatus is further used to actively scan the frequencies of the beacon signal and the electric signal that may be interfered and select a set of non-interfered frequency of the beacon signal and the electric signal based on the order. 
     In one embodiment, the touch sensitive processing apparatus is further used to emit the interfered signal of interfered frequency acquired by actively scanning. 
     In one embodiment, the transmitter is further used to emit the interfered signal of interfered frequency acquired by actively scanning. 
     One of the features of the present invention is to provide a touch sensitive processing apparatus used to connect multiple first and second electrodes of a touch panel, select the electric signal received by at least one of the multiple first and second electrodes based on the signal strength of the electric signal emitted by a transmitter and received by the multiple first and second electrodes, and calculate a ratio of the electric signal included according to the electric signal received by the at least one electrode. 
     One of the features of the present invention is to provide a touch sensitive system including a touch panel and a touch sensitive processing apparatus connecting multiple first and second electrodes of the touch panel. The touch sensitive processing apparatus selects the electric signal received by at least one of the multiple first and second electrodes based on the signal strength of the electric signal emitted by a transmitter and received by the multiple first and second electrodes, and calculates a ratio of the electric signal included according to the electric signal received by the at least one electrode. 
     One of the features of the present invention is to provide a controlling method for a touch sensitive processing apparatus used to connect multiple first and second electrodes of a touch panel. The controlling method including selecting the electric signal received by at least one of the multiple first and second electrodes based on the signal strength of the electric signal emitted by a transmitter and received by the multiple first and second electrodes, and calculating a ratio of the electric signal included according to the electric signal received by the at least one electrode. 
     In one embodiment, the signal strength of the electric signal received by the at least one electrode is bigger than that of the electric signals received by other electrodes. 
     In one embodiment, when the touch sensitive processing apparatus selects multiple electrodes of the first and the second electrodes, it is further used to sum up the signal strength of the electric signal of the multiple electrodes and calculate a ratio of the summed electric signal included. In another embodiment, the multiple electrodes include one of the first electrodes and one of the second electrodes. 
     In one embodiment, the touch sensitive processing apparatus is further used to adjust the receiving value of the at least one electrode, and calculate a ratio of the electric signal included according to the electric signal received by the at least one electrode adjusted the receiving value. 
     In one embodiment, when the touch sensitive processing apparatus selects multiple electrodes of the first and the second electrodes, it is further used to adjust the receiving value of the multiple electrodes, and calculate a ratio of the electric signal included according to the electric signal received by the multiple electrodes adjusted the receiving value. 
     In one embodiment, the touch sensitive processing apparatus is further used to calculate a position of the transmitter based on the electric signal received by the multiple first and second electrodes, and select the electric signal received by at least one of the multiple first and second electrodes according to the position. 
     In one embodiment, the touch sensitive processing apparatus is further used to select the electric signal received by at least one of the multiple first and second electrodes based on the position in three areas. The three areas include a first area that the position is around the intersection of one of the first electrodes and one of the second electrodes, a second area that the position is in the middle of two of the first electrodes and two of the second electrodes, and a third area that the position is not in the first and the second areas. In another embodiment, the position in the third area is on or around one of the first electrode or one of the second electrode. In another embodiment, when the position is in the first area, the touch sensitive processing apparatus is further used to select the one of the first electrodes and/or the one of the second electrodes; when the position is in the first area, the touch sensitive processing apparatus is further used to select the two of the first electrodes and/or the two of the second electrodes; and when the position is in the third area, the touch sensitive processing apparatus is further used to select the one of the first electrodes or the one of the second electrodes where the position is. 
     The above embodiments are only used to illustrate the principles of the present invention, and they should not be construed as to limit the present invention in any way. The above embodiments can be modified by those with ordinary skill in the art without departing from the scope of the present invention as defined in the following appended claims.