CN101692700A - Method and circuit for controlling audio signal channel of television - Google Patents
Method and circuit for controlling audio signal channel of television Download PDFInfo
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- CN101692700A CN101692700A CN200910190025A CN200910190025A CN101692700A CN 101692700 A CN101692700 A CN 101692700A CN 200910190025 A CN200910190025 A CN 200910190025A CN 200910190025 A CN200910190025 A CN 200910190025A CN 101692700 A CN101692700 A CN 101692700A
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- 230000005236 sound signal Effects 0.000 title claims abstract description 80
- 238000000034 method Methods 0.000 title claims abstract description 11
- 238000012360 testing method Methods 0.000 claims description 34
- 230000011664 signaling Effects 0.000 claims description 7
- 239000003990 capacitor Substances 0.000 claims description 3
- 238000001914 filtration Methods 0.000 claims description 3
- 238000001514 detection method Methods 0.000 abstract description 5
- 238000006073 displacement reaction Methods 0.000 description 4
- 238000004804 winding Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
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Abstract
The invention discloses a method and a circuit for controlling an audio signal channel of a television. The circuit comprises a signal processing main chip and a high-low level detection circuit, wherein an output end of the high-low level detection circuit is connected with the signal processing main chip; an input end of the high-low level detection circuit is connected with an audio signal input end of the television and is used for detecting whether the audio signal input end is accessed by an audio signal, outputting a high level to the signal processing main chip when the audio signal is input, and outputting a low level to the signal processing main chip when no audio signal is input; and the signal processing main chip is used for turning on the audio signal channel of the television when the high lever is received and shielding the audio signal channel when the low level is received. The method and the circuit make the signal processing main chip of the television capable of detecting and judging the audio signal, only when the audio signal is inserted, the audio channel is gated, and the adopted detection circuit is simple and has a lower cost.
Description
Technical field
The present invention relates to television set, relate in particular to a kind of audio signal channel control method and circuit of television set.
Background technology
(Audio Video, AV) inlet circuit is by having the winding displacement of certain-length (this length is by the structure and the size decision of television set), video and audio signal being sent into signal processing main chip handle to the audio-video signal of television set.This signal processing main chip is to the gating of video and voice-grade channel at present, be to judge by the synchronizing signal that detects in the vision signal, promptly as long as AV terminal is inserted vision signal, no matter whether plug audio signal simultaneously, master chip is gating sound, vision signal simultaneously all.
If but only interpolated video signal and epenthesis signal frequently not, because the winding displacement of transmit audio signals very easily is subjected near the interference of its big current signal, this disturbs can be through the amplification of audio power amplifier, if open television sound volume bigger, loudspeaker will send obvious noise.
Therefore be necessary prior art is improved.
Summary of the invention
The objective of the invention is to,, provide a kind of high-low level testing circuit, make the signal processing main chip of television set detect judgement, only ability gating voice-grade channel when inserting audio signal audio signal at the above-mentioned shortcoming of prior art.
Technical scheme of the present invention is:
A kind of tv audio signalling channel control circuit comprises signal processing main chip, and it also comprises a high-low level testing circuit; The output of described high-low level testing circuit connects described signal processing main chip, input connects the audio signal input end of television set, be used to detect whether incoming audio signal of described audio signal input end, and when the audio signal input is arranged, to described signal processing main chip output high level, when not having the audio signal input, to described signal processing main chip output low level;
Described signal processing main chip is used for when receiving described high level, turns on the audio signal channel of television set, when receiving described low level, shields described audio signal channel.
Control circuit of the present invention, wherein, described high-low level testing circuit comprises an emitter follower, the input of described emitter follower connects described audio signal input end;
Also comprise a testing circuit, the output of described emitter follower connects the input of described testing circuit;
Described testing circuit is used for when described audio signal input end has the audio signal input to described signal processing main chip output high level, output low level when not having the audio signal input.
Control circuit of the present invention, wherein, described testing circuit comprises first diode, and the positive pole of described first diode connects the output of described emitter follower, and negative pole connects the emitter-base bandgap grading and the power supply of the second positive-negative-positive triode;
The positive pole of described first diode connects the base stage of the second positive-negative-positive triode by the 4th bias resistance;
The collector electrode of the described second positive-negative-positive triode connects the base stage of the 3rd triode by bleeder circuit, the emitter grounding of described the 3rd triode, collector electrode is used to connect the signal processing main chip of television set, and exports testing result to described signal processing main chip.
Control circuit of the present invention, wherein, the collector electrode of the described second positive-negative-positive triode is used for the noise signal of filtering testing circuit by the 3rd filter capacitor ground connection.
Control circuit of the present invention, wherein, the emitter-base bandgap grading of the described second positive-negative-positive triode inserts supply voltage value, than the big at least 0.7V of audio signal voltage that described audio signal input end inserted.
A kind of tv audio signalling channel control method may further comprise the steps:
A, employing high impedance input mode are obtained the audio signal on the tv audio signal input part;
B, in audio signal when input, arranged when described audio signal input end, to the signal processing main chip output high level signal of television set, otherwise the output low level signal;
C, described signal processing main chip are turned on the audio signal channel of television set when receiving described high level signal.
Control method of the present invention wherein, in the described steps A, adopts emitter follower as high impedance input circuit.
After adopting the present invention program's circuit, carry out the various AV terminal circuit of sound, video signal transmission with winding displacement, when only slotting video input, when epenthesis was not imported frequently, even volume is reached bigger, loudspeaker can not send obvious noise yet, and the circuit that is adopted is simple, and cost is lower.
Description of drawings
Fig. 1 is the TV set circuit block diagram of the embodiment of the invention;
Fig. 2 is the high-low level testing circuit figure of the embodiment of the invention.
Embodiment
Below in conjunction with accompanying drawing, will be described in detail preferred embodiment of the present invention.
The tv audio signalling channel control circuit block diagram that the embodiment of the invention provided as shown in Figure 1, comprise signal processing main chip 300, also comprise a high-low level testing circuit 200, wherein, the audio signal input end 100 of the input termination AV terminal of high-low level testing circuit 200, the I/O mouth 300 of the signal processing main chip of output termination television set, be used to detect whether incoming audio signal of audio signal input end, and when the audio signal input is arranged, to signal processing main chip output high level, when not having the audio signal input, to the signal processing main chip output low level.The I/O mouth of signal processing main chip is turned on the audio signal channel of television set when receiving high level, when receiving low level, and the shielding audio signal channel.
The high-low level testing circuit of present embodiment comprises an emitter follower, and the input of emitter follower connects audio signal input end; Also comprise a testing circuit, the input of the output connection detection circuit of emitter follower; Testing circuit is used for exporting high level to signal processing main chip when audio signal input end has the audio signal input, output low level when not having the audio signal input.
One of concrete schematic diagram of high-low level testing circuit of present embodiment as shown in Figure 2, form emitter follower circuit by the first coupling capacitance C1, the first divider resistance R1, the second divider resistance R2, the first triode V1, the 3rd resistance R 3 and the second capacitance C2, its effect is to provide a great input impedance (being about 100K Ω) to the audio signal of importing, guarantee that the high-low level testing circuit exerts an influence hardly to the audio signal of input itself, realizes undistorted input.
The input of emitter follower is connected audio signal input end, and output connects the positive pole of the first diode VD1, and the negative pole of the first diode VD1 connects the emitter-base bandgap grading and the power supply of the second positive-negative-positive triode; The positive pole of first diode connects the base stage of the second positive-negative-positive triode V2 by the 4th bias resistance R4; The collector electrode of the second positive-negative-positive triode V2 connects the base stage of the 3rd triode V3 by bleeder circuit, and the emitter grounding of the 3rd triode V3, current collection be the test signal end very, is used for testing result is exported to the signal processing main chip of television set.The collector electrode of the second positive-negative-positive triode can pass through the 3rd filter capacitor C3 ground connection, is used for the noise signal of filtering testing circuit.Wherein the 5th divider resistance R5 and the 6th divider resistance R6 constitute described bleeder circuit, bias current are provided for the base stage of the 3rd triode V3.
In this circuit, audio signal directly obtains from the audio signal input end of AV terminal, behind the last second capacitance C2 of emitter follower circuit, obtains the almost completely the same signal of audio signal that provides with external input device.The audio frequency signal amplitude scope of standard signal source input is generally-0.75V～0.75V, the second positive-negative-positive triode V2 saturation conduction, the base stage of the 3rd triode V3 is a high level, the 3rd triode V3 saturation conduction, test signal end output low level, promptly when AV terminal was plugged audio signal, the I/O mouth of television signal processing main chip received a low level; When AV terminal did not have epenthesis frequency signal, the second positive-negative-positive triode V2 and the 3rd triode V3 ended, and the test signal end is to high level of I/O mouth of the signal processing main chip of output television set.
The signal processing main chip of television set cooperates software operation according to the detected high-low level of I/O mouth, when the I/O mouth detects low level, makes the voice-grade channel gating of this master chip, and the TV function is play image and the sound of AV; When I/O detects high level, make master chip turn-off voice-grade channel, stop noise.
Among the above embodiment, the emitter-base bandgap grading of the second positive-negative-positive triode V2 is connected than the big power supply of 0.7V at least of audio signal voltage that audio signal input end inserted, to guarantee the V2 normally.As connect+during the 5V power supply, audio frequency signal amplitude is as long as in-4.3V～4.3V scope, all exportable correct test signal of the collector electrode of V2.
Need to prove that the second positive-negative-positive triode V2 also can adopt NPN type triode in the present embodiment, but can need more element to realize same effect, is not preferred plan therefore.And adopt the positive-negative-positive triode, then can realize by simple elements.Also can each parameter of foregoing circuit suitably be adjusted according to actual input audio signal situation.
The embodiment of the invention also provides a kind of tv audio signalling channel control method, may further comprise the steps:
Employing high impedance input mode is obtained the audio signal on the tv audio signal input part, as adopting emitter follower as high impedance input circuit, to avoid distorted signals;
When audio signal input end has the audio signal input, to the signal processing main chip output high level signal of television set, otherwise the output low level signal;
Signal processing main chip can produce control signal when receiving high level signal, turn on the audio signal channel of television set.
The specific implementation of this method can be with reference to the described physical circuit of front embodiment.
After adopting the audio signal channel control circuit that has the high-low level testing circuit of above embodiment, carry out the various AV terminal circuit of sound, video signal transmission with winding displacement, when only slotting video input, when epenthesis is not imported frequently, even volume is reached bigger, loudspeaker can not send obvious noise yet, and the circuit that is adopted is simple, and cost is lower.
Should be understood that, for those of ordinary skills, can be improved according to the above description or conversion, and all these improvement and conversion all should belong to the protection range of claims of the present invention.
Claims (7)
1. a tv audio signalling channel control circuit comprises signal processing main chip, it is characterized in that, also comprises a high-low level testing circuit; The output of described high-low level testing circuit connects described signal processing main chip, input connects the audio signal input end of television set, be used to detect described audio signal input end whether the audio signal input is arranged, and when the audio signal input is arranged, to described signal processing main chip output high level, when not having the audio signal input, to described signal processing main chip output low level;
Described signal processing main chip is used for when receiving described high level, turns on the audio signal channel of television set, when receiving described low level, shields described audio signal channel.
2. control circuit as claimed in claim 1 is characterized in that, described high-low level testing circuit comprises an emitter follower, and the input of described emitter follower connects described audio signal input end;
Also comprise a testing circuit, the output of described emitter follower connects the input of described testing circuit; Described testing circuit is used for output high level when described audio signal input end has the audio signal input, output low level when not having the audio signal input.
3. control circuit as claimed in claim 2 is characterized in that described testing circuit comprises first diode, and the positive pole of described first diode connects the output of described emitter follower, and negative pole connects the emitter-base bandgap grading and the power supply of the second positive-negative-positive triode;
The positive pole of described first diode connects the base stage of the second positive-negative-positive triode by the 4th bias resistance;
The collector electrode of the described second positive-negative-positive triode connects the base stage of the 3rd triode by bleeder circuit, the emitter grounding of described the 3rd triode, collector electrode is used to connect the signal processing main chip of television set, and exports testing result to described signal processing main chip.
4. control circuit as claimed in claim 3 is characterized in that, the collector electrode of the described second positive-negative-positive triode is used for the noise signal of filtering testing circuit by the 3rd filter capacitor ground connection.
5. control circuit as claimed in claim 3 is characterized in that, the emitter-base bandgap grading of the described second positive-negative-positive triode inserts supply voltage value, than the big at least 0.7V of audio signal voltage that described audio signal input end inserted.
6. tv audio signalling channel control method may further comprise the steps:
A, employing high impedance input mode are obtained the audio signal on the tv audio signal input part;
B, in audio signal when input, arranged when described audio signal input end, to the signal processing main chip output high level signal of television set, otherwise the output low level signal;
C, described signal processing main chip are turned on the audio signal channel of television set when receiving described high level signal.
7. control method as claimed in claim 6 is characterized in that, in the described steps A, adopts emitter follower as high impedance input circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910190025A CN101692700A (en) | 2009-09-10 | 2009-09-10 | Method and circuit for controlling audio signal channel of television |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910190025A CN101692700A (en) | 2009-09-10 | 2009-09-10 | Method and circuit for controlling audio signal channel of television |
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| CN101692700A true CN101692700A (en) | 2010-04-07 |
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| CN200910190025A Pending CN101692700A (en) | 2009-09-10 | 2009-09-10 | Method and circuit for controlling audio signal channel of television |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103209346A (en) * | 2013-03-06 | 2013-07-17 | 北京赛科世纪数码科技有限公司 | Noise control device |
| CN103840642A (en) * | 2012-11-27 | 2014-06-04 | 美的集团股份有限公司 | Electromagnetic heating device and drive circuit thereof |
| CN106792141A (en) * | 2016-12-12 | 2017-05-31 | 深圳Tcl数字技术有限公司 | The control method for playing back and device of tv audio |
| CN107889025A (en) * | 2017-11-28 | 2018-04-06 | 刘宏波 | Audio signal conversion equipment and method |
| CN115037899A (en) * | 2021-03-04 | 2022-09-09 | 湖北视拓光电科技有限公司 | Automatic detection type analog video transmission interface based on audio jack |
-
2009
- 2009-09-10 CN CN200910190025A patent/CN101692700A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103840642A (en) * | 2012-11-27 | 2014-06-04 | 美的集团股份有限公司 | Electromagnetic heating device and drive circuit thereof |
| CN103209346A (en) * | 2013-03-06 | 2013-07-17 | 北京赛科世纪数码科技有限公司 | Noise control device |
| CN106792141A (en) * | 2016-12-12 | 2017-05-31 | 深圳Tcl数字技术有限公司 | The control method for playing back and device of tv audio |
| CN107889025A (en) * | 2017-11-28 | 2018-04-06 | 刘宏波 | Audio signal conversion equipment and method |
| CN115037899A (en) * | 2021-03-04 | 2022-09-09 | 湖北视拓光电科技有限公司 | Automatic detection type analog video transmission interface based on audio jack |
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Application publication date: 20100407 |