CN201479352U - Audio adjusting circuit of earphone sender - Google Patents
Audio adjusting circuit of earphone sender Download PDFInfo
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- CN201479352U CN201479352U CN200920134322XU CN200920134322U CN201479352U CN 201479352 U CN201479352 U CN 201479352U CN 200920134322X U CN200920134322X U CN 200920134322XU CN 200920134322 U CN200920134322 U CN 200920134322U CN 201479352 U CN201479352 U CN 201479352U
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Abstract
The utility model provides an audio adjusting circuit of earphone sender, comprising a signal input end, two signal output ends, and a bias circuit for providing operation bias potential to the audio adjusting circuit of earphone sender; wherein the signal input end is connected with an earth terminal via a first capacitor and a second capacitor in turn, the first signal output end is connected with the signal input end via a third capacitor, the output end of the bias circuit is connected with the signal input end via a first resistance, the second signal output end is connected with one end of a fourth capacitor, the other end of the fourth capacitor is grounded via the second capacitor, and the output end of the bias circuit is connected with the other end of the fourth capacitor via a second resistance. The audio adjusting circuit of earphone sender can improve common mode restraining ratio of the whole circuit, to realize better shield and improve audio quality.
Description
Technical field
The utility model relates to voicefrequency circuit, relates in particular to earphone transmitting terminal audio frequency and adjusts circuit.
Background technology
Along with the miniaturization of electronic product and the variation of function, camera function for example, multi-media player function, wireless signal transmission function or the like, the complexity more thereby the mainboard circuit placed on it in more and more little design space that makes electronic product becomes, various circuit are mixed in together, the cabling of the functional circuit of various piece and layout are easy to cause interference each other, especially under the more numerous and diverse situation of the motherboard power supply of electronic product, earth signal between each circuit very easily is subjected to the interference of peripheral circuits, thereby causes the output information of corresponding circuits to be subjected to great influence.
In addition, more and more universal along with electronic product, and more user tends to use earphone to converse, and must effectively handle the audio signal of product in the communication process for this reason, guarantees high-quality voice call effect.
The utility model content
Thereby the purpose of this utility model is to overcome in the prior art earphone transmitting terminal audio frequency to adjust the easy transmitted noise of circuit and advance the shortcoming that microphone causes unnecessary interference, provide a kind of earphone transmitting terminal audio frequency to adjust circuit, the audio signal that this circuit obtains has voice call quality preferably.
Inventor of the present utility model finds that it mainly is because the very easily interference of other circuit of signal of circuit ground end that the easy transmitted noise of existing earphone transmitting terminal audio frequency adjustment circuit advances microphone.Fig. 1 is that the normal earphone transmitting terminal audio frequency that adopts is adjusted circuit in the prior art.As shown in fig. 1, MIC+ is a microphone input signal, the audio signal of output is MIC_P and MIC_N, input signal MIC+ adjusts circuit through the earphone transmitting terminal audio frequency in the scope shown in Fig. 1 frame of broken lines and forms two-way output signal MIC_P, MIC_N particularly, and above-mentioned two-way output signal is sent on the electronic product mainboard in the baseband processing chip as differential signal.HSED_BIAS among the figure is the bigoted voltage of microphone work.As can be seen from Figure 1 earphone transmitting terminal audio frequency is adjusted between circuit ground end and the output MIC_N by one first resistance R 10, is reached capacitance C40 and be in series.Because the space of electronic product mainboard is quite limited, under a lot of situations, the noise that can take place to be received by earth terminal exports MIC_N to by first resistance R 10 and capacitance C10, causes unnecessary interference, thereby cause earphone transmitting terminal noise very big, had influence on user's speech quality.Circuit shown in Figure 1 also is subjected to the influence of EMC (Electro MagneticCompatibility, electromagnetic compatibility) easily in the electronic product communication process simultaneously, is in particular the audio performance that is subjected to conducted interference under the talking state.
In order to solve above-mentioned deficiency, the earphone transmitting terminal audio frequency modulate circuit that provides of the present utility model, has a signal input part, and two signal output parts, one biasing circuit provides the work bias voltage for this earphone transmitting terminal audio frequency modulate circuit, signal input part is successively by first electric capacity, and second electric capacity link to each other with earth terminal, first signal output part links to each other with signal input part by the 3rd electric capacity, the output of biasing circuit links to each other with described signal input part by one first resistance, it is characterized in that, the secondary signal output links to each other with an end of one the 4th electric capacity, the other end of described the 4th electric capacity is by described second capacity earth, and the output of biasing circuit also links to each other with the other end of described the 4th electric capacity by one second resistance.
Described signal input part is the microphone signal input, and the resistance of described first resistance and second resistance equates, and the resistance of above-mentioned two resistance can be the resistance of microphone internal resistance.
Also by one the 5th capacity earth, an end of first resistance links to each other with the output of described biasing circuit the output of described biasing circuit, and the other end of first resistance is by one the 6th capacity earth.
Earphone transmitting terminal audio frequency modulate circuit two signal output parts of the present utility model form the conditioning that path is realized input signal by first to fourth electric capacity respectively, have effectively avoided being exported to by the noise signal of earth terminal two signal output parts of earphone transmitting terminal audio frequency modulate circuit.Simultaneously, the output of bias voltage forms the loop by two resistance and first signal output part, secondary signal output respectively, make the level basically identical at two signal output part places, be that the positive pole of microphone and the level of negative pole are in poised state, improved the common-mode rejection ratio that entire headset starts to hold the audio frequency modulate circuit, reached good shield effectiveness, improved the voice quality of conversation, EMC immunity to interference preferably also is provided.
Description of drawings
Fig. 1 is the audio frequency transmitting terminal schematic diagram of prior art;
Fig. 2 is embodiment circuit theory diagrams of the present utility model.
The realization of the purpose of this utility model, functional characteristics and advantage will be in conjunction with the embodiments, are described further with reference to accompanying drawing.
Embodiment
The utility model provides an earphone transmitting terminal audio frequency modulate circuit.This circuit has a signal input part, and two signal output parts, one biasing circuit provides the work bias voltage for this earphone transmitting terminal audio frequency modulate circuit, signal input part is successively by first electric capacity, and second electric capacity link to each other with earth terminal, first signal output part links to each other with signal input part by the 3rd electric capacity, the output of biasing circuit links to each other with described signal input part by one first resistance, wherein, the secondary signal output links to each other with an end of one the 4th electric capacity, the other end of described the 4th electric capacity is by described second capacity earth, and the output of biasing circuit also links to each other with the other end of described the 4th electric capacity by one second resistance.Also by one the 5th capacity earth, an end of first resistance links to each other with the output of described biasing circuit the output of described biasing circuit, and the other end of first resistance is by one the 6th capacity earth.
Further, described signal input part is the microphone signal input, and the resistance of described first resistance and second resistance equates.
See also Fig. 2, Fig. 2 is the schematic diagram of the circuit of the utility model one embodiment, and the circuit application in the present embodiment is in mobile phone.In is a microphone input signal among the figure; The audio signal of output is out+ and out-, and above-mentioned two-way output signal (out+, out-) is sent on the electronic product mainboard in the baseband processing chip as differential signal; Outp is the output of the biasing circuit of microphone work, described biasing circuit provides bias voltage for microphone work, microphone in the general mobile phone end needs the voltage bias ability operate as normal of 1v～3v, and the outp output voltage in the present embodiment can be provided by the baseband chip in the mobile phone.Biasing circuit output outp is by capacitor C 5 ground connection, and capacitor C 5 is filter capacitors of biasing circuit, guarantees that the voltage of biasing circuit output does not have ripple.The value of capacitor C 5 can be 0.1uf
Signal input part in is connected with capacitor C 3, the other end of capacitor C 3 is the first signal output part out+, signal input part in also links to each other with capacitor C 1 one ends, the other end of capacitor C 1 is connected with capacitor C 2 and capacitor C 4 respectively, the other end of capacitor C 4 is secondary signal output out-, the other end ground connection of capacitor C 2.Capacitor C 6 is connected in an end of capacitor C 3, the other end ground connection of capacitor C 6.Above-mentioned capacitor C 3, C4 be two signal output parts (out+, out-) capacitance respectively, capacitor C 2, C6 are used to suppress the difference mode signal between the signal output part (out+, out-), and capacitor C 1 is used to suppress the common-mode signal between the signal output part (out+, out-).Capacitor C 1, C2, C3, C4, C5 can be 100pf, 33pf, 0.1uf, 0.1uf, 33pf respectively.
Resistance R 1 is connected in an end of biasing circuit output outp and capacitor C 3, and resistance R 2 is connected in an end of biasing circuit output outp and capacitor C 4.Resistance R 1 can be identical resistance with resistance R 1, preferably, resistance R 1, R2 select the internal driving of the employed microphone device of mobile phone, like this can be so that microphone is under the normal biasing, but thereby good operation, resistance R 1, R2 are chosen as the resistance of 2.2k ohm in the present embodiment.In addition, the resistance of resistance R 1, R2 is the same can be so that signal output part out+, out-output signal-balanced, stable can better suppress the environmental noise that microphone is introduced.
From the above, earphone transmitting terminal audio frequency modulate circuit two signal output parts of the present utility model form the conditioning that path is realized input signal by first to fourth electric capacity respectively, have effectively avoided being exported to by the noise signal of earth terminal two signal output parts of earphone transmitting terminal audio frequency modulate circuit.Simultaneously, the output of bias voltage forms the loop by two resistance and first signal output part, secondary signal output respectively, make the level basically identical at two signal output part places, be that the positive pole of microphone and the level of negative pole are in poised state, improved the common-mode rejection ratio that entire headset starts to hold the audio frequency modulate circuit, reached good shield effectiveness, improved the voice quality of conversation, EMC immunity to interference preferably also is provided.Circuit of the present utility model is built by simple device can reach above-mentioned effect, and the economize on hardware resource reduces cost effectively.
The above only is a preferred embodiment of the present utility model; be not so limit claim of the present utility model; every equivalent structure or equivalent flow process conversion that utilizes the utility model specification and accompanying drawing content to be done; or directly or indirectly be used in other relevant technical fields, all in like manner be included in the scope of patent protection of the present utility model.
Claims (4)
1. earphone transmitting terminal audio frequency modulate circuit, has a signal input part, and two signal output parts, one biasing circuit provides the work bias voltage for this earphone transmitting terminal audio frequency modulate circuit, signal input part is successively by first electric capacity, and second electric capacity link to each other with earth terminal, first signal output part links to each other with signal input part by the 3rd electric capacity, the output of biasing circuit links to each other with described signal input part by one first resistance, it is characterized in that, the secondary signal output links to each other with an end of one the 4th electric capacity, the other end of described the 4th electric capacity is by described second capacity earth, and the output of biasing circuit also links to each other with the other end of described the 4th electric capacity by one second resistance.
2. want 1 described earphone transmitting terminal audio frequency modulate circuit according to right, it is characterized in that described first resistance is identical with the resistance of second resistance.
3. earphone transmitting terminal audio frequency modulate circuit according to claim 2 is characterized in that described signal input part is the microphone signal input, and the resistance of described first resistance and second resistance is the resistance of microphone internal resistance.
4. earphone transmitting terminal audio frequency modulate circuit according to claim 1, it is characterized in that, also by one the 5th capacity earth, an end of first resistance links to each other with the output of described biasing circuit the output of described biasing circuit, and the other end of first resistance is by one the 6th capacity earth.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200920134322XU CN201479352U (en) | 2009-07-29 | 2009-07-29 | Audio adjusting circuit of earphone sender |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200920134322XU CN201479352U (en) | 2009-07-29 | 2009-07-29 | Audio adjusting circuit of earphone sender |
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| Publication Number | Publication Date |
|---|---|
| CN201479352U true CN201479352U (en) | 2010-05-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200920134322XU Expired - Fee Related CN201479352U (en) | 2009-07-29 | 2009-07-29 | Audio adjusting circuit of earphone sender |
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| CN (1) | CN201479352U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102026063A (en) * | 2010-11-26 | 2011-04-20 | 中兴通讯股份有限公司 | Pseudo differential audio input circuit and installation method thereof |
| CN102497472A (en) * | 2011-11-29 | 2012-06-13 | 惠州Tcl移动通信有限公司 | Lung capacity test system based on microphone of mobile phone |
| WO2016119487A1 (en) * | 2015-01-30 | 2016-08-04 | 中兴通讯股份有限公司 | Audio input circuit and electronic terminal |
-
2009
- 2009-07-29 CN CN200920134322XU patent/CN201479352U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102026063A (en) * | 2010-11-26 | 2011-04-20 | 中兴通讯股份有限公司 | Pseudo differential audio input circuit and installation method thereof |
| CN102026063B (en) * | 2010-11-26 | 2014-12-10 | 中兴通讯股份有限公司 | Pseudo differential audio input circuit and installation method thereof |
| CN102497472A (en) * | 2011-11-29 | 2012-06-13 | 惠州Tcl移动通信有限公司 | Lung capacity test system based on microphone of mobile phone |
| WO2016119487A1 (en) * | 2015-01-30 | 2016-08-04 | 中兴通讯股份有限公司 | Audio input circuit and electronic terminal |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20100519 Termination date: 20160729 |