Abstract:
A tuner at least comprises a filter, a low noise amplifier, a mixer, a local oscillator, a frequency selector and a power management module, and the tuner is characterized in that the power management module includes a power detection means which has a first terminal connected to an input terminal of the tuner for detecting the power level of the input terminal and a second terminal connected to the low noise amplifier, and a power management means which has a first terminal connected to a third terminal of the power detection means for reducing the power consumption of the tuner by means of the power management module which makes the tuner operative under the optimum condition for power consumption.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention is related to a tuner, more particularly, is related to a tuner including a power manage module and the tuner uses the power manage module to detect the power level of the input power and control the power consumption and performance of the tuner according to the value of the power level. 
         [0003]    2. Description of the Prior Art 
         [0004]    Because the improvement of the communicative and the depressive technique, the global television broadcast system is switched from analog to digital. The change of the digital TV broadcast will trigger the high development of the relative industry, such as Set-Top-Box (STB) or high definition television (HDTV). In future, the digital TV broadcast will go mobile and the TV shows will be available at anytime and anywhere. Therefore, the tuner circuit in the STB and HDTV is a key issue in the industry. 
         [0005]      FIG. 1A  is a view of a conventional tuner included single conversion with intermediate frequency (IF). As shown in  FIG. 1A , the tuner  100  includes a filter  101 , a low noise amplifier  102  (LNA), a mixer  106 , a local oscillator  110  and a filter  112 . The filter  101  and the filter  112  are SAW filter. The radio frequency (RF) (such as frequency within 50˜860 MHz) received by the antenna (not shown) of the tuner  100  is transmitted from the filter  101  to the LNA  102  to be amplified. Then, the mixer  106  and the local oscillator  110  are used to decrease the amplified radio frequency to be the frequency within the intermediate frequency range, such as 36 MHz. The filter  112  is used to select the suitable channel. 
         [0006]      FIG. 1B  is a view of a conventional tuner included dual conversion with IF. As shown in  FIG. 1B , the tuner  100  includes a low noise amplifier  102  (LNA), an IF/RF mixer  106   a,  a band-pass filter  104 , an IF/IF mixer  106   b,  and a filter  112 . One end of the low noise amplifier  102  is connected the antenna and the low noise amplifier  102  amplifiers the radio frequency. Then, the mixer  106   a  and the local oscillator  110 A are used to increase the amplified radio frequency to be the frequency within the intermediate frequency range, such as 1 GHz. One end of the mixer  106   a  is connected to the output end of the low noise amplifier. The local oscillator  110 A is connected to another end of the mixer  106   a  and used to provide a frequency of the local oscillator, such as 1 GHz˜2 GHz. Then, the input end of the band-pass filer  104  is connected to the output end of the mixer  106   a  and used to filer the noise and output the intermediate frequency from another end. The mixer  106   b  and the local oscillator  110 B are used to decrease the first intermediate frequency to be the second intermediate frequency. The filter  112  is used to select the suitable channel. Moreover, the filter  112  can be a channel select filter that used to select a desired channel and filter other unwanted channels. Obviously, the tuner with the dual conversion with IF is able to filter the mirror signals without using a lot of filters. 
         [0007]      FIG. 1C  is a view of a conventional tuner including a dual conversion with low IF. As shown in  FIG. 1C , the radio frequency is transmitted into the low noise amplifier  102  to be amplified and divided into I Path and Q Path by a RF poly-phase filter. Then the frequency is transmitted into the complex mixer (also called dual quadrature mixer). The complex mixer  114  is made by a plurality of mixers  106 . The quadrature local oscillator  111  will transmit the oscillated frequency to the complex mixer  114  to be mixed into I Path and Q Path quadrature low IF. The quadrature local oscillator  111  is generated by the local oscillator  111  and a divider  110  (such as divided by 2). Another IF poly-phase filter  113  will transform the I Path and Q Path low IF quadrature signal to be the I Path and Q Path low IF signal to decrease the frequency and filter the mirror frequency. At final, the channel select filter is used to select the desired channel and filter other unwanted channels. Therefore, the function of the tuner is completed. 
         [0008]      FIG. 1D  is a view of a conventional tuner including dual conversion with low IF. As shown in  FIG. 1D , the radio frequency is transmitted into the low noise amplifier  102  to be amplified, and increased the frequency to be IF and mixed into in-phase frequency  1  (IIF 1 ) and quadrature phase by a first quadrature mixer  120  and a first quadrature LO  117 . Then the frequency is mixed into quadrature low IF of the IIF 1  and the QIF 1  by the complex mixer  122  and the second quadrature LO  119 . The IF poly-phase filter  118  is used to transform the quadrature low IF signals of the IIF 1  and the QIF 1  into low IF signals to decrease the frequency and filter the mirror frequency. The channel select filter  116  is used to select the desired channel and filter other unwanted channels. Therefore, the function of the tuner is completed. 
         [0009]    In each of the tuner described above, when the strength of the radio frequency is changed, such as the user end is far away from the transmitted station, the radio signal transmitted to the user end is extremely weak. The low noise amplifier is necessary to be adjusted in the maximum gain to amplify the weak signals. When the user end is closed to the transmitted station, the radio signal transmitted to the user end is extremely weak. The low noise amplifier is necessary to be adjusted in the minimum gain to avoid the signal saturation. Therefore, a new circuit structure used to detect the power level of the radio frequency in the tuner is disclosed in the present invention and the gain and the current of the low noise amplifier is able to adjust. The tuner can work at the better power consumption with better performance. 
       SUMMARY OF THE INVENTION 
       [0010]    According to the background of the invention described above, in order to satisfy the requirement of the industry, the main object of the present invention is to provide a tuner structure and the tuner is able to work at the optimum power consumption to decrease the power consumption of the tuner. 
         [0011]    Another object of the present invention is to provide a tuner structure and the tuner is able to work at the optimum consumption and the best performance condition. 
         [0012]    One another object of the present invention is to provide a frequency inversion device and the frequency inversion device is able to work at the optimum power consumption to decrease the power consumption of the tuner. 
         [0013]    One another object of the present invention is to provide a frequency inversion device and the frequency inversion device is able to at the optimum consumption and the best performance condition. 
         [0014]    A frequency conversion device comprising at least one low noise amplifier, a mixer, a local oscillator and a power manage module is characterized at: the power manage module comprising a power detector and a first end of the power detector is connected to the input end of the frequency conversion device and used to detect the power level of the input end, and the second end is connected to the low noise amplifier; and a power manage device and a first end of the power manage device is connected to the low noise amplifier. 
         [0015]    A dual frequency conversion device comprising a serial connection of a first single frequency conversion device and a second single frequency conversion device and the first single frequency conversion device and the second single frequency conversion device includes a low noise amplifier, a mixer, an oscillator and a power manage module and is characterized by the power manage module comprising: a power detector and a first end of the power detector is connected to the input end of the frequency conversion device and used to detect the power level of the input end, and the second end is connected to the low noise amplifier; and a power manage device and a first end of the power manage device is connected to the low noise amplifier. 
         [0016]    A tuner comprising a filter, a low noise amplifier, a mixer, a local oscillator, a frequency selector and a power manage module is characterized by the power manage module comprising: a power detector and a first end of the power detector is connected to the input end of the frequency conversion device and used to detect the power level of the input end, and the second end is connected to the low noise amplifier; and a power manage device and a first end of the power manage device is connected to the low noise amplifier. 
         [0017]    A tuner comprising a poly-phase filter, a low noise amplifier, a complex mixer, a quadrature local oscillator, a frequency selector and a power manage module is characterized by the power manage module comprising: a power detector and a first end of the power detector is connected to the input end of the frequency conversion device and used to detect the power level of the input end, and the second end is connected to the low noise amplifier; and a power manage device and a first end of the power manage device is connected to the low noise amplifier. 
         [0018]    A tuner comprising a serial connection of a first single frequency conversion device and a second single frequency conversion device, a filter, a low noise amplifier, and the first single frequency conversion device includes a mixer, a local oscillator, a frequency selector and a power manage module and the second single frequency conversion device includes a mixer, a local oscillator, a frequency selector and a power manage module and is characterized by the power manage module of the first single frequency conversion device comprising: a power detector and a first end of the power detector is connected to the input end of the frequency conversion device and used to detect the power level of the input end, and the second end is connected to the low noise amplifier; a power manage device and a first end of the power manage device is connected to the low noise amplifier; and the power manage module of the second single frequency conversion device comprising: a power detector and a first end of the power detector is connected to the input end of the frequency conversion device and used to detect the power level of the input end, and the second end is connected to the low noise amplifier; and a power manage device and a first end of the power manage device is connected to the low noise amplifier. 
         [0019]    A tuner comprising a serial connection of a first single frequency conversion device and a second single frequency conversion device, and the first single frequency conversion device includes a filter, a low noise amplifier, a mixer, a local oscillator, a frequency selector and a power manage module and the second single frequency conversion device includes a mixer, a local oscillator, a frequency selector and a power manage module and is characterized by: the power manage module comprising: a power detector and a first end of the power detector is connected to the input end of the frequency conversion device and used to detect the power level of the input end, and the second end is connected to the low noise amplifier; and a power manage device and a first end of the power manage device is connected to the low noise amplifier. 
         [0020]    An adjust method of a tuner, comprising: providing a tuner and the tuner includes a filter, a low noise amplifier, a mixer, a local oscillator, a frequency selector and a power manage module; executing a power detecting to receive a radio frequency of the tuner and detect a power level of the radio frequency by an input end of a power detector; executing a power programming to determine the power level and output a controlled signal by a power manage device; and executing a power adjusting to adjust the gain of the low noise amplifier by the controlled signal. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
           [0022]      FIG. 1A  is a view of a conventional tuner included single conversion with IF; 
           [0023]      FIG. 1B  is a view of a conventional tuner included dual conversion with IF; 
           [0024]      FIG. 1C  is a view of a conventional tuner included dual conversion with low IF; 
           [0025]      FIG. 1D  is a view of a conventional tuner including dual conversion with low IF; 
           [0026]      FIG. 2  is a view showing a tuner with power manage module in the present invention; 
           [0027]      FIG. 3  is a view showing a tuner with power manage module in another embodiment of the present invention; 
           [0028]      FIG. 4  is a view showing a tuner with power manage module in another embodiment of the present invention; 
           [0029]      FIG. 5  is a view showing a dual frequency conversion device with power manage module in the present invention; 
           [0030]      FIGS. 6A˜6B  are views showing the low noise amplifier in the present invention; 
           [0031]      FIGS. 7A˜7B  are views showing the low noise amplifier in another embodiment of the present invention; and 
           [0032]      FIG. 8  is a view showing the low noise amplifier in one another embodiment of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0033]    The detailed description of the present invention will be discussed in the following embodiments, which are not intended to limit the scope of the present invention, but can be adapted for other applications. While drawings are illustrated in details, it is appreciated that the quantity of the disclosed components may be greater or less than that disclosed, except expressly restricting the amount of the components. 
         [0034]      FIG. 2  is a view showing a tuner with single conversion with IF. The tuner is an over heterodyne tuner or a broadband tuner, such as digital TV tuner. As shown in  FIG. 2 , the tuner  200  includes a filter  101 , a low noise amplifier (LNA)  102 , a mixer  106 , a filter  112 , and a power manage module  210 . The power manage module includes a power detector  210  and a power manage device  220 . The filter  101  and the filter  112  are SAW filters. 
         [0035]    As shown in  FIG. 2 , the antenna (not shown) of the tuner will receive the radio frequency (frequency between 50˜860 MHz) and transmit the frequency to the low noise amplifier  102  after passing the filter  101 . The power detector  210  will detect the RF power level at the same time and transmit the power level value to the power manage device. For example, the power manage  220  is a power/current mode controller. In other words, the power detector  210  will transmit the power level to the low noise amplifier  102  to adjust the power operation of the low noise amplifier  102 . 
         [0036]    Still referring to  FIG. 2 , when the power manage device  220  receives the power level, it will determine the value of the power level. When the power level is a large signal, such as over 50 dbm, the power manage device  220  will set the tuner in the maximum current mode control condition and transmitting a current controlled signal to the low noise amplifier  102 , such as sending a minimum gain of the current controlling signal. Besides, in the preferred embodiment of the present invention, there is an automatic gain controlled circuit  230  disposed between the power detector  210  and the low noise amplifier  102 . The power detector  210  will transmit the power level to the automatic gain controlled circuit  230  first and then the automatic gain controlled circuit  230  will transmit the signal to the low noise amplifier  102 . Therefore, the low noise amplifier  102  can be operated in better power operation mode. In addition, the power manage device  220  is also able to connect with low noise amplifier  102 , the mixer  106  and any other components (not shown), as shown in  FIG. 2 . Therefore, when the power manage device  220  received the power level detected by the power detector  210 , the power manage device will adjust the current of the low noise amplifier  102  and/or the mixer  106  in accordance with the current power level. And also other components will be adjusted by the power manage device  220  at the same time, and those components can work compatibly with the low noise amplifier  102 . Moreover, in the same period, the power manage device  220  can control the current of the low noise amplifier  102  in accordance with the frequency of the local oscillator  110   a  to avoid the gain signal is big enough to be flowed to the mixer  106  or the local oscillator  110   a.  It would cause the problem of the frequency-shifted. Obviously, according to the operation of the power detector  210  and the power manage device  220  in the power manage module; the tuner  200  of the present invention can work in optimum power consumption and the optimum condition when the power level is too large. 
         [0037]    When the input power level is a small signal, such as less than 10 dbm, the power manage device  220  will set the tuner in the minimum current mode control and output a current controlled signal, such as the largest gain of the current controlled signal, to the low noise amplifier  102 . Similarly, in the preferred embodiment, there is an automatic gain controlled circuit  230  disposed between the power detector  210  and the low noise amplifier  102 . The power detector  210  will transmit the power level to the automatic gain controlled circuit  230  first and then the automatic gain controlled circuit  230  will transmit the signal to the low noise amplifier  102 . Therefore, the low noise amplifier  102  can be operated in better power operation mode. Similarly, the power manage device  220  is also able to connect with low noise amplifier  102 , the mixer  106  and any other components (not shown). Therefore, when the power manage device  220  received the power level detected by the power detector  210 , the power manage device  220  will adjust the current of the low noise amplifier  102  and/or the mixer  106  in accordance with the current power level. And also other components will be adjusted by the power manage device  220  at the same time, and those components can work compatibly with the low noise amplifier  102 . Obviously, according to the operation of the power detector  210  and the power manage device  220  in the power manage module; the tuner  200  of the present invention can work in optimum power consumption and the optimum condition when the power level is small. 
         [0038]    When the input power level is between 50 dbm and 10 dbm, such as 30 dbm, the power detector  210  won&#39;t change the gain of the low noise amplifier  102 . The low noise amplifier  102  is operated in the normal standard mode, such as the gain is configured in a linear operative range. The power manage device  220  is able to adjust the current of the low noise amplifier  102  and/or mixer  106  in accordance with the current power level. And also other components will be adjusted by the power manage device  220  at the same time, and those components can work compatibly with the low noise amplifier  102 . The tuner  200  of the present invention can work in optimum power consumption and the optimum condition. 
         [0039]    As the description above, when the low noise amplifier  102  will amplify the radio frequency by a suitable gain in accordance with the controlled signal transmitted by the automatic gain controlled circuit  230 . The amplified signal is divided into intermediate frequency, such as 36 Hz, by a mixer and a local oscillator  110   a.    
         [0040]    Besides, it should be noted that the power manage module of the present invention is able to be composed with the low noise amplifier  102 , the mixer  106  and the local oscillator  10   a  to be a frequency conversion apparatus. As shown in  FIG. 3 , it can form an up-conversion device or a down-conversion device according to the high or low of the oscillated frequency of the local oscillator. At final, another filter  112  is used to filter some unwanted channel and the tune function of the tuner is accomplished. 
         [0041]    The input signal is not just a radio frequency signal. For example, when the input is an intermediate frequency signal, the present embodiment is able to achieve the function described above. When the power manage module, the low noise amplifier  102 , the mixer  106  and the local oscillator  110   a  are together formed a down-conversion device and are able to connect with the power detector  210  and the power manage device  220  of the power module. And there is also an automatic gain controlled device disposed between the power detector  210  and the low noise amplifier  230 . Therefore, the frequency conversion device of the present invention can work in optimum power consumption and the optimum condition. 
         [0042]      FIG. 4  is a view showing a single conversion tuner. The tuner  200  includes a low noise amplifier  102 , a first poly-phase filter  105 , a complex mixer  114 , a quadrature local oscillator  111 , a second poly-phase filter  113 , a frequency selector  116  and a power manage module. And the power manage module includes a power detector  210  and a power manage device  220 . As shown in  FIG. 4 , when the radio frequency is transmitted to the tuner, the power detector  210  will detect the power level of the input radio frequency. Then, the power level is transmitted to the power manage device  220 , such as a power/current mode controlled device. In other words, the power detector  210  also will transmit the power level to the low noise amplifier  102  to adjust the power operation of the low noise amplifier  102 . When the power mange device  220  receives the power level, it will determine the value of the power level. When the input power level is large, such as over than 50 dbm, the power manage device  220  will set the tuner in the maximum current control mode and send a current controlled signal to the low noise amplifier, such as sending a minimum gain of the current controlling signal. In the preferred embodiment of the present invention, there is an automatic gain controlled circuit  230  disposed between the power detector  210  and the low noise amplifier  102 . The power detector  210  will transmit the power level to the automatic gain controlled circuit  230  first and then the automatic gain controlled circuit  230  will transmit the signal to the low noise amplifier  102 . Therefore, the low noise amplifier  102  can be operated in better power operation mode. In addition, the power manage device  220  is also able to connect with low noise amplifier  102 , the first poly-phase filer  105 , the complex mixer  114  and any other components (not shown), as shown in  FIG. 4 . Therefore, when the power manage device  220  received the power level detected by the power detector  210 , the power manage device  220  will adjust the current of the low noise amplifier  102  in accordance with the current power level. And also the first poly-phase filter  105 , the complex mixer  114  and other components will be adjusted by the power manage device  220  at the same time, and those components can work compatibly with the low noise amplifier  102 . Moreover, in the same period, the power manage device  220  can control the gain of the low noise amplifier  102  in accordance with the frequency of the local oscillator  110   a  to avoid the gain signal is big enough to be flowed to the mixer  106  or the local oscillator  110   a.  It would cause the problem of the frequency-shifted. Obviously, according to the operation of the power detector  210  and the power manage device  220  in the power manage module; the tuner  200  of the present invention can work in optimum power consumption and the optimum condition when the power level is too large. 
         [0043]    When the input power level is a small signal, such as less than 10 dbm, the power manage device  220  will set the tuner in the minimum current mode control and output a current controlled signal, such as the largest gain of the current controlled signal, to the low noise amplifier  102 . Similarly, in the preferred embodiment, there is an automatic gain controlled circuit  230  that disposed between the power detector  210  and the low noise amplifier  102 . The power detector  210  will transmit the power level to the automatic gain controlled circuit  230  first and then the automatic gain controlled circuit  230  will transmit the signal to the low noise amplifier  102 . Therefore, the low noise amplifier  102  can be operated in better power operation mode. Similarly, the power manage device  220  is also able to connect with low noise amplifier  102 , the first poly-phase filter  105 , the complex mixer  114  and any other components (not shown). Therefore, when the power manage device  220  received the power level detected by the power detector  210 , the power manage device  220  will adjust the current of the low noise amplifier  102 , the first poly-phase filter  105  and the complex mixer  106  in accordance with the current power level. And also other components will be adjusted by the power manage device  220  at the same time, and those components can work compatibly with the low noise amplifier  102 . Obviously, according to the operation of the power detector  210  and the power manage device  220  in the power manage module; the tuner  200  of the present invention can work in optimum power consumption and the optimum condition when the power level is small. 
         [0044]    When the input power level is between 50 dbm and 10 dbm, such as 30 dbm, the power detector  210  will not change the gain of the low noise amplifier  102 . The low noise amplifier  102  is operated in the normal standard mode, such as the gain is configured in a linear operative range. The power manage device  220  is able to adjust the current of the low noise amplifier  102 , the poly-phase filter  105  and the complex mixer  114  in accordance with the current power level. And also other components will be adjusted by the power manage device  220  at the same time, and those components can work compatibly with the low noise amplifier  102 . The tuner  200  of the present invention can work in optimum power consumption and the optimum condition. 
         [0045]    The low noise amplifier  102  will amplify the radio frequency with the power level in accordance with the controlled signal transmitted from the automatic gain controlled device  230  and the frequency is divided into I path and Q path by the RF poly-phase filter  105 . The signals are respectively transmitted into the complex filter  114  (also called dual quadrature mixer). The complex mixer  114  is made by a plurality of mixer  106 . The quadrature LO  111  will transmit the oscillated signal to the complex filter  114  to be mixed into I path and Q path&#39;s quadrature low IF signal. Another filter IF poly-phase filter  113  will converse the quadrature low IF signal into low IF signal in I Path and Q path. 
         [0046]    Obviously, the basic structures in  FIG. 2  and  FIG. 4  are the similar. The different in  FIG. 2  and  FIG. 4  is that the change of the filter and the mixer. The quadrature LO  111  is used to generate the quadrature phase by a phase divided circuit  115  and the local oscillator  110  (such as divided by 2). 
         [0047]    Now,  FIG. 5  is a view showing a dual conversion tuner. The dual conversion tuner is made by two signal conversion units serially connected to each other. The pre-stage circuit includes a low noise amplifier  102 , a radio/intermediate frequency mixer  106   b,  a local oscillator  10   a  and a power manage module. The post-stage circuit includes a low noise amplifier  102 , an intermediate/intermediate mixer  106   a,  a local oscillator  110   b  and a power manage module. In the present embodiment, the power manage module includes a power detector  210  and a power manage device  220 . There is also an automatic gain controlled circuit  230  disposed between the power detector  210  and the low noise amplifier  102 . In addition, the single conversion unit in the pre-stage circuit is able to form an up-conversion unit by the local oscillator  110   a,  as the oscillated frequency of the local oscillator is 1 GHz˜2 GHz. The signal conversion unit in post-stage is able to form a down-conversion unit by the local oscillator  110   b,  as the oscillated frequency of the local oscillator is 1 GHz. 
         [0048]    Because the dual conversion tuner is made by two single conversion unit serially connected to each other, the operation in each one of the single conversion unit and the power manage module is the same as the embodiments shown in  FIG. 2 ,  FIG. 3  and  FIG. 4 . Therefore, the detail description of the dual conversion tuner is omitted. It should be noted that, in practical, only the single conversion unit (up-conversion unit) in pre-stage works with the power manage module but the single conversion unit (down-conversion unit) in post-stage doesn&#39;t not work with power manage module. Also, only the single conversion unit (down-conversion unit) in post-stage works with the power manage module but the single conversion unit (up-conversion unit) in pre-stage doesn&#39;t not work with power manage module. Those are embodiments in the present invention, it is not limited herein. 
         [0049]    In addition, in order to let the tuner of the present invention in good performance mode, a low noise amplifier used to adjust automatically the input impedance in accordance with the input radio signal is provided in the present invention. The detail description is in the following. 
         [0050]      FIG. 6A  is a view showing the low noise amplifier of the present invention. The low noise amplifier  1  includes a first active component  10 , a second active component  12  and a plurality of adjustable attenuation device  20 ,  22 . Each one of the active component in the low noise amplifier  1  includes a first end, a second end and a third end. In the present embodiment, the active components are BJT and the first end is a base end, the second end is the emitter end and the third end is a collector end. Besides, the adjustable attenuation devices  20 ,  22  are components with two ends, such as resistance, inductance, capacitance, diode and any combination above. The adjustable attenuation devices can be the component with three ends, such as BJT, FET, MOSFET or CMOS. 
         [0051]    Please still referring to  FIG. 6A , the base ends of the first active component  10  and the second active component  12  are connected to the input end and used to receive the broadband radio frequency fed from the antenna of the tuner. When the first adjustable attenuation device  20  is a two ends component, the first end is connected to the base end of the first active component  10  and the second end is connected to the emitter end of the second active component  12 . Besides, the second adjustable attenuation device  22  is a two ends component too, the first end is connected to the base end of the first active component  10  and the second end is connected to the emitter end of the second active component  12 . Obviously, the voltage (V B1 ) of the base end of the first active component  10  and the voltage V E2  of the emitter end of the second active component  12  can be adjusted or changed to change the impedance of the adjustable attenuation device  20 . The voltage (V E1 ) of the emitter end of the first active component  10  and the voltage V B2  of the base end of the second active component  12  can be adjusted or changed to change the impedance of the adjustable attenuation device  22 . therefore, when the gains of the first active component  10  and the second active component  12  in the low noise amplifier of the present invention are adjusted, such as adjusting the gain o f the low noise amplifier by a power manage device, the input impedance of the low noise amplifier  1  is changeable in a small range, for example the input impedance is changeable within 50±2Ω. Therefore, the tuner and the low noise amplifier can maintain in the optimum compatible impedance condition. Certainly, before the input signal is transmitted from the antenna of the tuner to the low noise amplifier  1 , the input signal is optionally transmitted to amplifier circuit (not shown), such as an automatic gain controlled circuit. 
         [0052]    Besides, in order to adjust the input impedance, the adjustable attenuation device  20  and  22  can be the adjustable component, such as adjustable resistance, adjustable inductance, adjustable capacitance and so on. The third end (such as collector end) of the first active component  10  and the second active component  12  is connected to the two ends component (not shown) to be the load of the low noise amplifier  1 . The two ends component is resistance, inductance, capacitance, diode or any combinations above. 
         [0053]    Now referring to  FIG. 6B ,  FIG. 6B  is a view showing another embodiment of the low noise amplifier in the present invention. The base ends of the first active component  10  and the second active component  12  are connected to the input end and used to receive the broadband radio frequency fed from the antenna of the tuner. When the first adjustable attenuation device  20  is a three ends component, such as a BJT, the third end (such as collector) is connected to the base end of the second active component  12  and the second end (such as emitter) is connected to the emitter of the first active component  10  and the first end (such as base) is connected to a voltage control end V ctl2  used to adjust voltage. Obviously, the voltage (V B1 ) of the base end of the first active component  10  and the voltage V E2  of the emitter end of the second active component  12  are adjusted or changed to adjust the voltage V ctl1  of the voltage controlled end of the adjustable attenuation device  20  to change the impedance of the adjustable attenuation device  20 . Similarly, the voltage (V B2 ) of the base end of the second active component  12  and the voltage V E1  of the emitter end of the first active component  10  are adjusted or changed to adjust the voltage V ctl1  of the voltage controlled end of the adjustable attenuation device  20  to change the impedance of the adjustable attenuation device  20 . Therefore, when the gains of the first active component and the second active component in the low noise amplifier of the present invention are adjusted, such as adjusting the gain of the low noise amplifier by a power manage device, the input impedance of the low noise amplifier  1  is changeable in a small range, for example the input impedance is changeable within the 75±5Ω. Therefore, the tuner and the low noise amplifier can maintain in the optimum compatible impedance condition. Certainly, before the input signal is transmitted from the antenna of the tuner to the low noise amplifier  1 , the input signal is optionally transmitted to amplifier circuit (not shown), such as an automatic gain controlled circuit. 
         [0054]    Besides, in order to adjust the input impedance, the adjustable attenuation device  20  and  22  can be BJT, FET, MOSFET or CMOS. In the preferred embodiment, the voltage value of the voltage controlled end (V ctl1 , V ctl2 ) can be chosen to be zero voltage. The third end (such as collector end) of the first active component  10  and the second active component  12  is connected to the two ends component (not shown) to be the load of the low noise amplifier  1 . The two ends component is resistance, inductance, capacitance, diode or any combinations above. 
         [0055]    Besides, the first adjustable attenuation device  20  and  22  shown in  FIG. 6A  and  FIG. 6B  of the present invention can be a plurality of components being parallel to each other. In other words, the first adjustable attenuation device  20  and the second adjustable attenuation device  22  can be formed by a plurality of adjustable attenuation devices being parallel connection. 
         [0056]      FIG. 7A  is a view showing the low noise amplifier in another embodiment of the present invention. As shown in  FIG. 7A , the low noise amplifier  2  includes a first active component  30 , a second active component  32  and a plurality of adjustable attenuation device  40 ,  42 . The active components  30  and  32  are FET, MOSFET, CMOS and so on. The first end is a gate end, the second end is the source end and the third end is a drain end. Besides, the adjustable attenuation devices  40 ,  42  are components with two ends, such as resistance, inductance, capacitance, diode and any combination above. Besides, the adjustable attenuation devices  40 ,  42  are components with three ends, such as BJT, FET, MOSFET, CMOS and so on. 
         [0057]    Obviously, the circuit structure in  FIG. 7A  is the same as the structure shown in  FIG. 6A  and  FIG. 6B . The first active component is replaced from BJT to FET, MOSFET or CMOS. In the present embodiment, the NMOS is chosen to be the active component. 
         [0058]    Please still referring to  FIG. 7A , the gate ends of the first active component  30  and the second active component  32  are connected to the input end and used to receive the broadband radio frequency fed from the antenna of the tuner. When the first adjustable attenuation device  40  is a two ends component, the first end is connected to the gate end (V G1 ) of the first active component  30  and the second end is connected to the source end (V S2 ) of the second active component  32 . Besides, as the second adjustable attenuation device  42  is a two ends component too, the first end is connected to the gate end (V G2 ) of the second active component  32  and the second end is connected to the source end (V S2 ) of the first active component  30 . Obviously, when the gain of the low noise amplifier in the present invention is adjusted (such as a power manage module used to adjust the gain of the low noise amplifier), the input impedance of the low noise amplifier  2  can be adjusted within a small range, such as the impedance is within 50±2Ω, by the connection of the first adjustable attenuation device  40  and the second adjustable attenuation device  42 . Therefore, the tuner and the low noise amplifier can maintain in the optimum compatible impedance condition. Certainly, before the input signal is transmitted from the antenna of the tuner to the low noise amplifier  2 , the input signal is optionally transmitted to amplifier circuit (not shown), such as an automatic gain controlled circuit. 
         [0059]    Moreover, in order to adjust the input impedance, the adjustable attenuation device  40  and  42  can be the adjustable component, such as adjustable resistance, adjustable inductance, and adjustable capacitance and so on. The third ends (such as drain ends) of the first active component  30  and the second active component  32  are connected to the two ends component (not shown) to be the load of the low noise amplifier  2 . The two ends component is resistance, inductance, capacitance, diode or any combinations above. 
         [0060]    Now referring to  FIG. 7B , which is a view showing another embodiment of the low noise amplifier in the present invention. The gate ends of the first active component  30  and the second active component  32  in the low noise amplifier  2  are connected to the input end and used to receive the broadband radio frequency fed from the antenna of the tuner. When the first adjustable attenuation device  40  is a three ends component, such as a NMOS, the third end (such as drain end) is connected to the gate end (V G1 ) of the first active component  30  and the second end (such as source end) is connected to the source end (V S2 ) of the second active component  32  and the first end (such as gate end) is connected to a voltage control end Vctl 1  used to adjust voltage. Besides, when the second adjustable attenuation device  42  is a three ends component (such as a NMOS), the third end (such as drain end) is connected to the gate end (V G2 ) of the second active component  32  and the second end (such as source end) is connected to the source end (V S1 ) of the first active component  30  and the first end (such as gate end) is connected to a voltage control end V ctl2  used to adjust voltage. 
         [0061]    Obviously, the voltage (V G1 ) of the gate end of the first active component  30  and the voltage V S2  of the source end of the second active component  12  are adjusted or changed to be a fixed voltage value and the voltage of the voltage controlled end V ctl1  of the first adjustable attenuation device  40  is changed to a suitable voltage value, then the impedance of the adjustable attenuation device  20  is adjustable. Similarly, the voltage (V S1 ) of the source end of the first active component  30  and the voltage (V G2 ) of the gate end of the second active component  32  are adjusted or changed and the voltage of the voltage controlled end V ctl2  of the adjustable attenuation device  42  is adjusted, then the impedance of the adjustable attenuation device  42  is adjustable. Therefore, according to the connection of the adjustable attenuation device  40  or  42 , the input impedance of the low noise amplifier  2  is changeable in a small range, for example the input impedance is changeable within the 75±5Ω. Therefore, the tuner and the low noise amplifier can maintain in the optimum compatible impedance condition. Certainly, before the input signal is transmitted from the antenna of the tuner to the low noise amplifier  2 , the input signal is optionally transmitted to amplifier circuit (not shown), such as and automatic gain controlled circuit. 
         [0062]    Besides, in order to adjust the input impedance, the adjustable attenuation device  40  and  42  can be BJT, FET, MOSFET or CMOS. In the preferred embodiment, the voltage value of the voltage controlled end V ctl1 , V ctl2 ) can be chosen to be zero voltage. The third ends (such as drain ends) of the first active component  30  and the second active component  32  are connected to the two ends component (not shown) to be the load of the low noise amplifier  2 . The two ends component is resistance, inductance, capacitance, diode or any combinations above. 
         [0063]    In addition, the first adjustable attenuation device  40  and  42  as shown in  FIG. 7A  and  FIG. 7B  of the present invention can be a plurality of components being parallel to each other. In other words, the first adjustable attenuation device  40  and the second adjustable attenuation device  42  can be formed by a plurality of adjustable attenuation devices being parallel connection. 
         [0064]      FIG. 8  is a view showing another embodiment of the low noise amplifier in the present invention. As shown in  FIG. 8 , the low noise amplifier  3  includes a first active component  30 , a second active component  32 , a third active component  34 , a forth active component  36  and a plurality of adjust attenuation device  40  and  42 . The adjustable attenuation devices can be BJT, FET, MOSFET or CMOS. The first end is a gate end, the second end is the source end and the third end is a drain end. Besides, the adjustable attenuation devices  40 ,  42  are components with two ends, such as resistance, inductance, capacitance, diode and any combination above. Besides, the adjustable attenuation devices  40 ,  42  are components with three ends, such as BJT, FET, MOSFET, CMOS and so on. 
         [0065]    Obviously, the circuit structure of the embodiment shown in  FIG. 8  is the same as the circuit shown in  FIG. 7A  and  FIG. 7B . In  FIG. 8 , the active components  34  and  36  are respectively connected to the active components  30  and  32  shown in  FIG. 7A  and  FIG. 7B . The third end (drain) of the active component  30  is connected to the second end (source) of the active component  34 . Besides, the third end (drain) of the active component  34  is connected to a load device and the first end (gate) of the active component  34  is connected to the ground. The object to add an active component  34  and an active component  36  is to increase the output impedance of the low noise amplifier. 
         [0066]    Obviously, the circuit structure in  FIG. 8  is the same as the structure shown in  FIG. 6A  and  FIG. 6B . The active components  10  and  12  are connected to an active component. The active component is a BJT, FET, MOSFET or CMOS. Because the circuit structure and the operated procedure are similar to the description above, the detail description is omitted herein. 
         [0067]    Obviously, the low noise amplifier in  FIG. 6  to  FIG. 8  is a low noise amplifier able to automatically adjust the input impedance in accordance with the radio frequency. The low noise amplifier can replace the low noise amplifier in  FIG. 2 ,  FIG. 3 ,  FIG. 4 , and  FIG. 5 . Moreover, it should be noted that because the improvement of the semiconductor manufacture technique, so the tuner, the low noise amplifier, the mixer, the oscillator power detector, power/current controlled device and the automatic gain controlled device is above to be made with a die and formed a tuner with system on chip. 
         [0068]    Although specific embodiments have been illustrated and described, it will be appreciated by those skilled in the art that various modifications may be made without departing from the scope of the present invention, which is intended to be limited solely by the appended claims.