Abstract:
An apparatus ( 10 ) for adjusting sound volume for an audio system includes a controller ( 101 ) connected to an amplifier ( 40 ) of the audio system for controlling amplification of the amplifier, and a first circuit ( 102 ) for adjusting the sound volume. The controller includes a microprogrammed control unit ( 1010 ), a random-access memory ( 1012 ), and an electrically erasable programmable read-only memory ( 1014 ). The first circuit includes an attenuation circuit ( 1022 ) connected to a tuner of the audio system for attenuating input audio signals, and a switch ( 1024 ). An input end of the switch is connected to the tuner and an output end of the attenuation circuit, and an output end of the switch is connected to an audio processor ( 30 ) of the audio system. The apparatus enables a user to freely adjust an average level of sound produced by the audio system, and simultaneously avoid being bothered by loud transmissions.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is related to a copending U.S. patent application entitled “APPARATUS AND METHOD FOR ADJUSTING SOUND VOLUME FOR TELEVISIONS AND OTHER AUDIO SYSTEMS”, filed on the same day with the same applicant and assignee as the invention. The disclosure of the above identified application is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to apparatuses and methods for adjusting and attenuating sound volume for televisions and other audio systems.  
         [0004]     2. Description of Prior Art  
         [0005]     At times, a television or radio may broadcast an unexpected, noisy transmission to a user due to a programming change or when there are problems with reception. For example, a television or radio program provider may intentionally broadcast an advertisement at an abruptly high volume so as to attract a user&#39;s attention. On other occasions, signals received by the television or radio may be interfered with by signals transmitted by other electronic devices, thereby generating static or other unwanted transmissions. Loud advertisements or unexpected noises are perhaps least likely to bother the user during the daytime or in an environment that is otherwise relatively noisy. However, the user is likely to be easily bothered late at night or in a relatively quiet environment.  
         [0006]     In order to overcome the above-mentioned problem, U.S. Pat. No. 5,130,665, issued on Jul. 14, 1992, discloses an audio volume controller. When the audio volume controller is in a control mode, the audio volume controller outputs audio signals whose volumes are between a predefined minimum volume and a predefined maximum volume. That is, the audio volume controller cannot output any audio signal whose volume is higher than the predefined maximum volume. This enables the user to avoid being bothered by loud noises. However, the user cannot freely adjust the average level of the sound produced by the audio volume controller in the control mode unless he/she switches the audio volume controller to exit the control mode. Thus, it is not convenient for the user to use the audio volume controller.  
       SUMMARY OF THE INVENTION  
       [0007]     Accordingly, a primary object of the present invention is to provide an apparatus for facilitating a user to not only freely adjust an average level of sound produced by an audio system according to his/her particular requirements, but also simultaneously avoid being bothered by loud transmissions.  
         [0008]     A second object of the present invention is to provide a method for facilitating a user to not only freely adjust an average level of sound produced by an audio system according to his/her particular requirements, but also simultaneously avoid being bothered by loud transmissions.  
         [0009]     In order to fulfill the above-mentioned primary object, the present invention provides an apparatus for adjusting sound volume for an audio system. The apparatus comprises a controller connected to an amplifier of the audio system for controlling amplification of the amplifier, and a first circuit for adjusting the sound volume. The controller comprises a microprogrammed control unit (MCU). The first circuit comprises an attenuation circuit for attenuating input audio signals, and a first switch. The attenuation circuit comprises: a first resistance, one end of the first resistance being connected to a tuner of the audio system; a second resistance, one end of the second resistance being connected to another end of the first resistance, and another end of the second resistance being grounded; a third resistance, one end of the third resistance being connected to the other end of the first resistance; a first diode, the cathode of the first diode being connected to another end of the third resistance, and the anode of the first diode being grounded; and a second diode, the anode of the second diode being connected to the other end of the third resistance, and the cathode of the second diode being grounded. An input end of the first switch is connected to the tuner of the audio system and the other end of the first resistance, and an output end of the first switch is connected to an audio processor of the audio system.  
         [0010]     In order to fulfill the above-mentioned second object, the present invention provides a method for adjusting sound volume for an audio system. The method comprises the following steps: (a) determining whether an apparatus for adjusting sound volume is in an attenuation mode; (b) controlling a first switch to switch a circuit for adjusting sound volume to an attenuation mode, if the apparatus for adjusting sound volume is in the attenuation mode; (c) attenuating an input audio signal, the input audio signal traveling through a first resistance and a second resistance if a first diode and a second diode do not allow the input audio signal through; and (d) repeating steps (a) through (c) until the audio system is turned off.  
         [0011]     Other objects, advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a simplified block diagram of part of a television having an apparatus for adjusting sound volume according to the present invention;  
         [0013]      FIG. 2  is a circuit diagram of an attenuation circuit of the apparatus of  FIG. 1 ;  
         [0014]      FIG. 3  is a graph of operation performance of the apparatus of  FIG. 1 ; and  
         [0015]      FIG. 4  is a flow chart of an exemplary method for adjusting sound volume according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]      FIG. 1  is a simplified block diagram of part of a television having an apparatus  10  for adjusting sound volume according to the present invention. The apparatus  10  can run in either of two operating modes: a normal mode and an attenuation mode. A viewer switches the apparatus  10  to either one of the above-mentioned operating modes by use of an infrared remote control device  50  or a functional key (not shown) on the television itself. The apparatus  10  comprises a controller  101 , and a circuit  102  for adjusting sound volume. The controller  101  comprises a microprogrammed control unit (MCU)  1010 , a Random-Access Memory (RAM)  1012 , and an Electrically Erasable Programmable Read-Only Memory (EEPROM)  1014 . The RAM  1012  and the EEPROM  1014  communicate with the MCU  1010 . The controller  101  controls amplification of an amplifier  40  of the television. In other exemplary embodiments, the EEPROM  1014  may be replaced by any other suitable nonvolatile memory, such as a Read-Only Memory (ROM), an Erasable and Programmable Read-Only Memory (EPROM) or a flash memory.  
         [0017]     The operating mode of the circuit  102  corresponds to the operating mode of the apparatus  10 . When the apparatus  10  is in the normal mode, the circuit  102  is also in a normal mode; similarly, when the apparatus  10  is in the attenuation mode, the circuit  102  is also in an attenuation mode. The circuit  102  comprises an attenuation circuit  1022 , and a switch  1024  for switching the operating mode of the circuit  102 . Input ends of the attenuation circuit  1022  and the switch  1024  are connected to a tuner  20  of the television. The output end of the attenuation circuit  1022  is connected to an input end of the switch  1024 . The MCU  1010  is connected to the switch  1024 , for controlling the switch  1024  to switch the operating mode of the circuit  102  according to the operating mode of the apparatus  10 . The switch  1024  is connected to an audio processor  30 , for outputting thereto unadjusted audio signals or audio signals attenuated by the attenuation circuit  1022 .  
         [0018]      FIG. 2  is a circuit diagram of the attenuation circuit  1022 . In the present embodiment, the attenuation circuit  1022  comprises a mechanical switch S, five resistances R 1 , R 2 , R 3 , R 4 , R 5 , and twelve diodes D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 8 , D 9 , D 10 , D 11 , D 12 . An input end of the resistance R 1  is connected to the tuner  20  of the television. The switch  1024  (see  FIG. 1 ) and input ends of the other four resistances R 2 , R 3 , R 4 , R 5  are connected to an output end of the resistance R 1  in parallel. An output end of the resistance R 2  is grounded. An output end of the resistance R 3  is connected to the cathode of the diode D 1  and the anode of the diode D 2 . An output end of the resistance R 4  is connected to the cathode of the diode D 3  and the anode of the diode D 5 . The anode of the diode D 3  is connected to the cathode of the diode D 4 , and the cathode of the diode D 5  is connected to the anode of the diode D 6 . An output end of the resistance R 5  is connected to the cathode of the diode D 7  and the anode of the diode D 10 . The anode of the diode D 7  is connected to the cathode of the diode D 8 , whose anode is connected to the cathode of the diode D 9 . The cathode of the diode D 10  is connected to the anode of the diode D 11 , whose cathode is connected to the anode of the diode D 12 . The anode of the diode D 1 , the cathode of the diode D 2 , the anode of the diode D 4 , the cathode of the diode D 6 , the anode of the diode D 9  and the cathode of the diode D 12  are connected to one end of the mechanical switch S in parallel. The other end of the mechanical switch S is grounded.  
         [0019]      FIG. 3  is a graph of operation performance of the apparatus  10 . The horizontal abscissa represents an audio signal Vi input to the apparatus  10 , and the vertical ordinate represents an audio signal Vo output by the apparatus  10 . A value Vim of the horizontal abscissa is a maximum possible audio signal input to the apparatus  10 . Values Voi and Vom of the vertical ordinate correspond to Vim, and are respectively a maximum possible unadjusted audio signal and a maximum possible attenuated audio signal output by the apparatus  10 . The input audio signal Vi may correspond to a television program, an advertisement, or an unexpected noise such as interference. When the viewer selects the normal mode of the apparatus  10  through the infrared remote control device  50  or the functional key on the television itself, the MCU  1010  controls the switch  1024  to switch the circuit  102  to the normal mode. In such case, audio signals transmitted by the tuner  20  of the television are input to the switch  1024 , and then transmitted to the audio processor  30  of the television. The thin, steep broken line of  FIG. 3  shows a relationship between the input audio signal Vi and the output audio signal Vo of the apparatus  10  in the normal mode. In short, the audio signal Vo output by the apparatus  10  in the normal mode is same as the audio signal Vi input thereto. The output audio signal Vo is obtained by the following equation: 
   Vo=Vi (0 ≦Vi≦Vim )  
         [0020]     When the viewer selects the attenuation mode of the apparatus  10  through the infrared remote control device  50  or the functional key on the television itself, the MCU  1010  controls the switch  1024  to switch the circuit  102  to the attenuation mode. In such case, the audio signals transmitted by the tuner  20  of the television are input to the attenuation circuit  1022 . If the viewer would like the input audio signal Vi to be attenuated slightly after traveling through the attenuation circuit  1022 , he/she may turn off the mechanical switch S so that the input audio signal Vi travels only through the resistance R 1  and the resistance R 2 . In such case, the thick, gentler-sloping broken line of  FIG. 3  shows the relationship between the input audio signal Vi and the output audio signal Vo of the apparatus  10  in the slight attenuation mode. A lower part of this broken line is obscured by a solid line (see explanation hereinbelow). The output audio signal Vo is obtained by the following equation: 
 
 Vo=Vi*R   2 /( R   1 + R   2 ) (S is off; 0≦Vi≦Vim) 
 
         [0021]     If the viewer would like the input audio signal Vi to be attenuated significantly after traveling through the attenuation circuit  1022 , he/she may turn on the mechanical switch S. According to electrical characteristics of a diode, the diode allows an input audio signal through only when a positive voltage of the input audio signal is the same as or higher than a threshold positive voltage of the diode. The threshold positive voltage is a voltage that enables the input audio signal to travel from the anode of the diode to the cathode thereof. Different diodes have different threshold positive voltages. For example, the threshold positive voltage of a silicon diode is typically 0.5V, whereas the threshold positive voltage of a germanium diode is typically 0.1V. A value Vi 1  of  FIG. 3  represents an input audio signal that the diode D 1  (or the diode D 2 ) barely allows through. A value Vi 2  of  FIG. 3  represents an input audio signal that the diodes D 1 , D 3 , D 4  (or the diodes D 2 , D 5 , D 6 ) barely allow through simultaneously. A value Vi 3  of  FIG. 3  represents an input audio signal that the diodes D 1 , D 3 , D 4 , D 7 , D 8 , D 9  (or the diodes D 2 , D 5 , D 6 , D 10 , DI 1 , D 12 ) barely allow through simultaneously.  
         [0022]     Accordingly, when the input audio signal Vi is lower than the value Vi 1 , it is not allowed through by any one of the diodes D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 8 , D 9 , D 10 , D 11 , D 12 . In such case, the input audio signal Vi travels through the resistances R 1 , R 2 . When the input audio signal Vi is between the value Vi 1  and the value Vi 2 , it is allowed through only by the diode D 1  (or the diode D 2 .) In such case, the input audio signal Vi travels through the resistances R 1 , R 2 , R 3 . When the input audio signal Vi is between the value Vi 2  and the value Vi 3 , it is allowed through by the diodes D 1 , D 3 , D 4  (or the diodes D 2 , D 5 , D 6 .) In such case, the input audio signal Vi travels through the resistances R 1 , R 2 , R 3 , R 4 . When the input audio signal Vi is between the value Vi 3  and the value Vim, it is allowed through by the diodes D 1 , D 3 , D 4 , D 7 , D 8 , D 9  (or the diodes D 2 , D 5 , D 6 , D 10 , D 11 , D 12 .) In such case, the input audio signal Vi travels through the resistances R 1 , R 2 , R 3 , R 4 , R 5 . Thus, the solid line of  FIG. 3  shows the relationship between the input audio signal Vi and the output audio signal Vo of the apparatus  10  in the significant attenuation mode. The output audio signal Vo is obtained by the following equations: 
 
 Vo=Vi*R   2 /( R   1 + R   2 ) (S is on; 0≦Vi≦Vi 1 ) 
 
 Vo=Vi*R   33 /( R   1 + R   33 ) (S is on; Vi 1 &lt;Vi≦Vi 2 ) 
 
 Vo=Vi*R   44 /( R   1 + R   44 ) (S is on; Vi 2 &lt;Vi≦Vi 3 ) 
 
 Vo=Vi*R   55 /( R   1 + R   55 ) (S is on; Vi 3 &lt;Vi≦Vim) 
 
         [0023]     The value R 33  represents a total resistance of the parallel-connected resistances R 2 , R 3 . The value R 44  represents a total resistance of the parallel-connected resistances R 2 , R 3 , R 4 . The value R 55  represents a total resistance of the parallel-connected resistances R 2 , R 3 , R 4 , R 5 . In electronics, the more parallel-connected resistances there are, the lower the total resistance. Consequently, the following relationship holds: R 2 /(R 1 +R 2 )&gt;R 33 /(R 1 +R 33 )&gt;R 44 /(R 1 +R 44 )&gt;R 55 /(R 1 +R 55 ). This means that the attenuation circuit  1022  attenuates the input audio signal Vi gradually. Further, the higher the input audio signal Vi is, the more it is attenuated. The audio signal Vo output by the attenuation circuit  1022  is an attenuated audio signal. The attenuated audio signal travels through the switch  1024  and the audio processor  30 , and then is broadcast by a speaker of the television after being amplified by the amplifier  40 . In this way, the viewer avoids being bothered by loud advertisements or unexpected noises.  
         [0024]     The resistances R 1 , R 2 , R 3 , R 4 , R 5  may be either the same or different, according to the particular requirements of a manufacturer of the television. In addition, the number of parallel-connected resistances and their corresponding diodes may be decreased according to the particular requirements of the manufacturer. In particular, the resistance R 5  and its corresponding diodes D 7 , D 8 , D 9 , D 10 , D 11 , D 12 , or/and the resistance R 4  and its corresponding diodes D 3 , D 4 , D 5 , D 6  may be omitted. Moreover, the number of parallel-connected resistances and their corresponding diodes may be increased according to the particular requirements of the manufacturer. Any additional parallel-connected resistances and their corresponding diodes have similar connections to those of the parallel-connected resistances R 1 , R 2 , R 3 , R 4 , R 5  and their corresponding diodes D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , D 7 , D 8 , D 9 , D 10 , D 11 , D 12 .  
         [0025]     When the apparatus  10  is in the attenuation mode, the viewer can simultaneously adjust sound volume via the infrared remote control device  50  or a functional key on the television itself according to his/her particular requirements. In order to realize the above-described function of adjusting sound volume, the MCU  1010  controls the degree to which the amplifier  40  amplifies the audio signals. The apparatus  10  of the present invention is also applicable to other audio systems besides televisions, such as radios, CD disc players and personal stereos.  
         [0026]      FIG. 4  is a flow chart of an exemplary method for adjusting sound volume according to the present invention. A viewer selects an operating mode of the apparatus  10  via the infrared remote control device  50  or a functional key on the television itself. At step S 510 , the MCU  1010  determines whether the apparatus  10  is in the attenuation mode. If so, the procedure goes to step S 512  described below. Otherwise, the procedure goes to step S 522 . At step S 522 , the MCU  1010  controls the switch  1024  to switch the circuit  102  to the normal mode. Then at step S 524 , the switch  1024  transmits an unadjusted audio signal to the audio processor  30 , whereupon the procedure is ended. At step S 512 , the MCU  1010  controls the switch  1024  to switch the circuit  102  to the attenuation mode. At step S 514 , the attenuation circuit  1022  receives the input audio signal. At step S 516 , the attenuation circuit  1022  attenuates the input audio signal. If the mechanical switch S is off, the input audio signal travels through the resistances R 1 , R 2 . If the mechanical switch S is on, the input audio signal travels through three or more of the resistances R 1 , R 2 , R 3 , R 4 , R 5 , depending on the level of the positive voltage of the input audio signal. The input audio signal travels through the resistances R 1 , R 2 , R 3  if the diode D 1  or the diode D 2  allows the input audio signal through. The input audio signal travels through the resistances R 1 , R 2 , R 3 , R 4  if the diodes D 1 , D 3 , D 4  or the diodes D 2 , D 5 , D 6  allow the input audio signal through. The input audio signal travels through the resistances R 1 , R 2 , R 3 , R 4 , R 5  if the diodes D 1 , D 3 , D 4 , D 7 , D 8 , D 9  or the diodes D 2 , D 5 , D 6 , D 10 , D 11 , D 12  allow the input audio signal through. At step S 518 , the switch  1024  obtains the attenuated audio signal from the attenuation circuit  1022 , and transmits the attenuated audio signal to the audio processor  30 .  
         [0027]     The above-described procedure is repeated continually from the time the viewer turns on the television until the time the viewer turns off the television.  
         [0028]     While a preferred embodiment and preferred method of the present invention have been described above, it should be understood that they have been presented by way of example only and not by way of limitation. Thus the breadth and scope of the present invention should not be limited by the above-described exemplary embodiment and method, but should be defined only in accordance with the following claims and their equivalents.