CN2694649Y - Microphone input circuit capable removing noises - Google Patents
Microphone input circuit capable removing noises Download PDFInfo
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- CN2694649Y CN2694649Y CN 200420044588 CN200420044588U CN2694649Y CN 2694649 Y CN2694649 Y CN 2694649Y CN 200420044588 CN200420044588 CN 200420044588 CN 200420044588 U CN200420044588 U CN 200420044588U CN 2694649 Y CN2694649 Y CN 2694649Y
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Abstract
The utility model relates to a microphone input circuit capable removing noises, for solving the problem that the existing vehicular telephone systems can not well remove microphone input noises. The microphone input circuit of the utility model comprises an omnidirectional microphone, a directional microphone, a phase inverter circuit, a same phase compound proportional circuit, a first amplifying circuit and a second amplifying circuit. Wherein the omnidirectional microphone is connected with the input end of the phase inverter circuit, and the directional microphone is connected with the input end of the first amplifying circuit; the phase inverter circuit and the output end of the first amplifying circuit are both connected with the input end of the same phase compound proportional circuit, and the output end of the same phase compound proportional circuit is connected with the input end of the second amplifying circuit. When an ambient noise signal in the input signal of the directional microphone is amplified to the same with the input signal of the omnidirectional microphone, the aim of removing noises can be obtained via the treatment of the same phase compound proportional circuit. The circuit of the utility model is simple, the effect of removing noises is obvious, and the speech quality of the vehicular telephone system can be raised.
Description
Technical field
The utility model relates to the circuit that is used to eliminate microphone noise in the audion system, be particularly related to a kind of microphone input circuit of removing noise, this circuit application after on-board telephone system, can be suppressed the diversity of settings noise in the communication process effectively, improve speech quality.
Background technology
Existing on-board telephone system adopts GSM or CDMA technology usually, and it can be with mobile phone and particularly family expenses or commercial car perfect adaptation of automobile, allows the people in the car keep phone be connected with the external world at any time; And usually all adopt the mode of hand-free call in the existing on-board telephone system, allow the user needn't hand microphone or receiver, when driving also can the interchange of safe and free ground thereby guarantee.
Because the particular surroundings of on-board telephone system self, during conversation automobile mostly be in started in addition driving process in, so background noise is strong especially, and be easy to generate same source noise, therefore, need special means and eliminate noise to improve speech quality.In the removal noise scheme of prior art, all be to adopt single noise source signal mostly, and the useful signal that receives is imported the denoising circuit with noise handle, this mode makes that levying the close noise signal of signal with thing is difficult to thoroughly be eliminated, the denoising effect is bad.
The utility model content
The utility model will solve existing on-board telephone system and fail well to eliminate the problem of microphone input noise, to improve the speech quality of on-board telephone system.
The technical scheme that its technical problem that solves the utility model adopts is: construct a kind of microphone input circuit of removing noise, comprise microphone and corresponding amplifying circuit, wherein also comprise negative circuit and be combined to ratio circuit together; Described microphone comprises omni-directional microphone and directional microphone; Described amplifying circuit comprises first amplifying circuit and second amplifying circuit; Described omni-directional microphone is connected to the input of described negative circuit, described directional microphone is connected to the input of described first amplifying circuit, the output of the described negative circuit and first amplifying circuit all is connected to described with the input that is combined to ratio circuit, the described input that is connected to described second amplifying circuit with the output that is combined to ratio circuit.
In the utility model, described being combined to ratio circuit is preferably an adder circuit together; In addition, in order to guarantee speech quality, preferably only be provided with a directional microphone in the utility model, but one or more omni-directional microphones can be set, described each omni-directional microphone can be parallel with one another.
In of the present utility model, directional microphone mainly receives the conversation voice signal, and ambient noise signal wherein is more weak; And omni-directional microphone mainly receives is ambient noise signal, and its ambient noise signal is stronger; When the background noise letter in the directional microphone input signal is amplified to when suitable with the omni-directional microphone input signal, because the latter is by anti-phase, so through with after being combined to ratio circuit and carrying out addition in 1: 1, both noise signals can be cancelled out each other, thereby can reach the purpose of removing noise.Circuit of the present utility model is simple, but it is very obvious to remove anti noise, can improve the speech quality of on-board telephone system greatly.
Description of drawings
The utility model is described in further detail below in conjunction with drawings and Examples, in the accompanying drawing:
Fig. 1 is the theory diagram of the utility model microphone input circuit;
Fig. 2 is the circuit diagram of a preferred embodiment of the utility model;
Fig. 3 a is the waveform schematic diagram of U02 among Fig. 2;
Fig. 3 b is the waveform schematic diagram of U0 among Fig. 2;
Fig. 3 c is the waveform schematic diagram of U03 among Fig. 2.
Embodiment
In the microphone input circuit of the present utility model, omni-directional microphone can receive the sound of a plurality of directions, and comprising background noise and caller's sound, and the overwhelming majority is a background noise; On the contrary, directional microphone receives only the sound of predetermined direction scope (even predetermined distance range in), can it be set to during assembling over against the driver, and mainly be caller's sound so it receives, certainly, the sub-fraction background noise is arranged also wherein.About the characteristic of omni-directional microphone and directional microphone, be that those skilled in the art know prior art, so no longer describe in detail herein.
As shown in Figure 1, wherein, the signal of omni-directional microphone being imported by negative circuit carries out anti-phase processing, only changes its phase place therebetween, can not change its amplitude.Simultaneously, by first amplifying circuit input signal of directional microphone is carried out processing and amplifying, can amplify conversation voice signal and ambient noise signal in its input signal in this step simultaneously, its mainly act on be wherein ambient noise signal is amplified to close with the signal of omni-directional microphone input; Then, the output signal of the output signal of negative circuit and first amplifying circuit sent into being combined to ratio circuit handle, to eliminate background noise, in this step normally with the addition in 1: 1 of two input signals, because it is close with the signal of omni-directional microphone input that the ambient noise signal that directional microphone is imported has been amplified to, and the input signal of omni-directional microphone is by anti-phase, so after two input signal additions, just in time ambient noise signal is cancelled out each other, only remaining conversation voice signal, thus reach the purpose of eliminating background noise; At last, by second amplifying circuit signal of removing behind the noise is amplified, and output to vehicle-mounted Circuits System.
A preferred embodiment of the present utility model as shown in Figure 2.As can be seen from the figure, operational amplifier A 1 is formed negative circuit, wherein Rf1=R1 with corresponding resistance R 1, Rf1; The input signal of omni-directional microphone is Ui, then has after handling by negative circuit: U0=-Rf1/R1 * Ui, because Rf1=R1, so U0=-Ui is arranged, promptly the size of signal and does not become but polarity becomes original opposite direction, thereby has reached anti-phase purpose.
The input signal U01 of directional microphone is input to first amplifying circuit of being made up of capacitor C 2, C4, resistance R 2, R3 and triode Q1 and carries out processing and amplifying, and its output signal is U02, and U02=β * U0 (β is the amplification coefficient of triode Q1); By the magnificationfactor that adjust to select adapts to, the ambient noise signal among the U02 can be amplified to the size of the output signal U 0 of negative circuit very approaching.
Be made up of operational amplifier A 2 and corresponding resistance R 7, R8, R8, R10 and R12 with being combined to ratio circuit, wherein R10=R7 comes down to an adder circuit.The output signal U 0 of negative circuit and the output signal U 02 of first amplifying circuit through resistance R 7, R10 input, have through after the calculation process: U03=Rf2 (U02/R10+U0/R7) respectively; Because it is close with U0 that the ambient noise signal among the U02 has been amplified to, and R10=R7, so for the background noise part, U02/R10+U0/R7=0 is arranged, U03=0 arranged promptly.In the said process only cancelling out each other of ambient noise signal can be taken place, the conversation voice signal of being imported in the directional microphone is also unaffected, ideally, ambient noise signal can be eliminated after cancelling out each other fully, and the conversation voice signal then can normally be input in the on-board telephone system.
Shown in Fig. 3 a, Fig. 3 b and Fig. 3 c, be respectively the waveform schematic diagram of U02 among Fig. 2, U0 and U03.Wherein, the situation after the signal that Fig. 3 a is depicted as directional microphone input is exaggerated, wherein containing the conversation sound waveform is the background noise waveform; Fig. 3 b is depicted as the signal of omni-directional microphone input by the situation after anti-phase, wherein only contains the background noise waveform; With Fig. 3 a and Fig. 3 b addition, the signal of background noise that can obtain the elimination shown in Fig. 3 c, so the signal of last output is mainly the conversation voice signal, most background noises can be suppressed, thereby reach the purpose of good elimination noise.
In addition, in order to guarantee speech quality, preferably only be provided with a directional microphone in the utility model, but one or more omni-directional microphones can be set, described each omni-directional microphone can be parallel with one another.
Claims (6)
1, a kind of microphone input circuit of removing noise comprises microphone and corresponding amplifying circuit, it is characterized in that,
Also comprise negative circuit and be combined to ratio circuit together;
Described microphone comprises omni-directional microphone and directional microphone;
Described amplifying circuit comprises first amplifying circuit and second amplifying circuit;
Described omni-directional microphone is connected to the input of described negative circuit, described directional microphone is connected to the input of described first amplifying circuit, the output of the described negative circuit and first amplifying circuit all is connected to described with the input that is combined to ratio circuit, the described input that is connected to described second amplifying circuit with the output that is combined to ratio circuit.
2, the microphone input circuit of removing noise according to claim 1 is characterized in that, all adopts NPN type triode as amplifying device in described first amplifying circuit and second amplifying circuit.
3, the microphone input circuit of removing noise according to claim 2 is characterized in that, in described first amplifying circuit, the base stage of triode Q1 connects described directional microphone through capacitor C 2, and its base stage also meets working power VCC through resistance R 2; Triode Q1 grounded emitter, collector electrode meets working power VCC through resistance R 3, and as the first amplifying signal output.
4, the microphone input circuit of removing noise according to claim 2, it is characterized in that, in described second amplifying circuit, the base stage of triode Q2 connects described with the output that is combined to ratio circuit through capacitor C 6, and its base stage also meets working power VCC through resistance R 5; Triode Q2 grounded emitter, collector electrode meets working power VCC through resistance R 6, and as the second amplifying signal output.
According to each described microphone input circuit of removing noise among the claim 1-4, it is characterized in that 5, described is an adder circuit with being combined to ratio circuit.
6, the microphone input circuit of removing noise according to claim 5 is characterized in that, wherein only is provided with a directional microphone, and is provided with one or more omni-directional microphones, and described each omni-directional microphone is parallel with one another.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200420044588 CN2694649Y (en) | 2004-04-05 | 2004-04-05 | Microphone input circuit capable removing noises |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200420044588 CN2694649Y (en) | 2004-04-05 | 2004-04-05 | Microphone input circuit capable removing noises |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2694649Y true CN2694649Y (en) | 2005-04-20 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200420044588 Expired - Fee Related CN2694649Y (en) | 2004-04-05 | 2004-04-05 | Microphone input circuit capable removing noises |
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| CN (1) | CN2694649Y (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101847501A (en) * | 2009-03-25 | 2010-09-29 | 爱三工业株式会社 | Resolver |
| CN101374178B (en) * | 2007-08-21 | 2011-01-19 | 华硕电脑股份有限公司 | Communication device |
| CN101964936A (en) * | 2010-10-09 | 2011-02-02 | 北京昆腾微电子有限公司 | Processing chip for digital microphone, input circuit thereof and digital microphone |
| CN101198235B (en) * | 2006-12-08 | 2011-05-18 | 美商富迪科技股份有限公司 | Electronic device and method for mounting microphone in the electronic device |
| CN105845147A (en) * | 2016-05-19 | 2016-08-10 | 成都零线科技有限公司 | Motor car broadcast simulation system |
| CN106026966A (en) * | 2016-05-12 | 2016-10-12 | 中国人民解放军国防科学技术大学 | Notch filtering method and circuit for GMI magnetic sensor |
| CN106057209A (en) * | 2016-05-19 | 2016-10-26 | 成都零线科技有限公司 | Airport broadcasting system |
| CN109104672A (en) * | 2018-08-27 | 2018-12-28 | 上海咔滨船舶装备有限公司 | Noise reduction circuit and microphone |
-
2004
- 2004-04-05 CN CN 200420044588 patent/CN2694649Y/en not_active Expired - Fee Related
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101198235B (en) * | 2006-12-08 | 2011-05-18 | 美商富迪科技股份有限公司 | Electronic device and method for mounting microphone in the electronic device |
| CN101374178B (en) * | 2007-08-21 | 2011-01-19 | 华硕电脑股份有限公司 | Communication device |
| CN101847501A (en) * | 2009-03-25 | 2010-09-29 | 爱三工业株式会社 | Resolver |
| CN101964936A (en) * | 2010-10-09 | 2011-02-02 | 北京昆腾微电子有限公司 | Processing chip for digital microphone, input circuit thereof and digital microphone |
| CN101964936B (en) * | 2010-10-09 | 2013-06-19 | 北京昆腾微电子有限公司 | Processing chip for digital microphone, input circuit thereof and digital microphone |
| CN106026966A (en) * | 2016-05-12 | 2016-10-12 | 中国人民解放军国防科学技术大学 | Notch filtering method and circuit for GMI magnetic sensor |
| CN106026966B (en) * | 2016-05-12 | 2018-09-25 | 中国人民解放军国防科学技术大学 | A kind of notch filter method and circuit for GMI Magnetic Sensors |
| CN105845147A (en) * | 2016-05-19 | 2016-08-10 | 成都零线科技有限公司 | Motor car broadcast simulation system |
| CN106057209A (en) * | 2016-05-19 | 2016-10-26 | 成都零线科技有限公司 | Airport broadcasting system |
| CN109104672A (en) * | 2018-08-27 | 2018-12-28 | 上海咔滨船舶装备有限公司 | Noise reduction circuit and microphone |
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Legal Events
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |