CN201965907U - Microphone device - Google Patents

Abstract

The utility model discloses a microphone device which comprises an input circuit, an echo eliminating circuit and an output circuit, as well as a power circuit, wherein the power circuit is connected at the input end of the input circuit and used for supplying power for the input end of the input circuit. The microphone device avoids power interference caused by shared power supply in the prior art through arranging the power circuit for independent power supply, so that the noise at the input end of the microphone device is lowered, and the whole tone quality of the microphone device is further improved.

Description

Microphone apparatus

Technical field

The utility model relates to the Audio Processing design field, particularly is used to improve the microphone apparatus of microphone tonequality.

Background technology

At present, in the use of microphone, find reflective generation through regular meeting.The generation of echo is owing to have the acoustics loop between loudspeaker and the microphone.Specifically, from the voice signal of far-end, connect the arrival near-end, and emit by the loudspeaker of near-end through communication.Behind voice signal process loudspeaker and the acoustics loop between the microphone that loudspeaker is emitted, collected by microphone.Then, the voice signal that is collected by microphone is passed far-end back again through the communication connection.At this moment, the speaker of far-end just can hear the echo of oneself, i.e. far-end echo.Described echo can have a strong impact on speech quality.

For solving above-mentioned echo problem, prior art has proposed the solution that multiple echo is eliminated, for example Chinese patent ZL200610144055.5 has just proposed a kind of microphone echo cancelling device and echo cancel method, comprise the frame length adjusting module in its device, be used to adjust data frame length, present frame and plurality of data are before united to form the Frame of length and adaptive frequency domain filter coefficient equal in length, to carry out auto adapted filtering.

Yet, though prior art is eliminated echo many solutions have been proposed, other new problems have also been found in the further raising of tonequality requirement when microphone is used.Existing power supply mode to microphone normally with shared one road power supply of other functional circuits, to cause outside power supply to disturb like this, thereby in the use of microphone, when for example using the hands-free phone conversation in car, bigger noise can be heard in the outer other end of car (conversation take over party).Described situation also will influence speech quality and for other voice applications of microphone.

The utility model content

The utility model provides a kind of microphone apparatus, and conversation receives the problem that can hear big noise when using to improve microphone.

For addressing the above problem, the utility model provides a kind of microphone apparatus, comprising: input circuit, echo cancel circuit and output circuit also comprise: power circuit, described power circuit is connected in the input end of input circuit, is used for the supplying power for input end to described input circuit.

Compared with prior art, the utility model microphone apparatus has the following advantages: by the power circuit of independent power supply is set, the power supply of avoiding the prior art common source and causing disturbs, improve the noise situations of described microphone apparatus input end, thereby improved the overall sound quality of microphone apparatus.

Description of drawings

Fig. 1 is a kind of embodiment block diagram of the utility model microphone apparatus;

Fig. 2 is a kind of embodiment circuit block diagram of the utility model microphone apparatus;

Fig. 3 is the another kind of embodiment circuit block diagram of the utility model microphone apparatus.

Embodiment

With reference to shown in Figure 1, a kind of embodiment of the utility model microphone apparatus comprises:

Input circuit 100 is used to receive the microphone audio input signal, after described microphone audio input signal being carried out the voltage gain processing, described microphone audio input signal is transferred to wave filter;

Power circuit 200 is to the supplying power for input end ofinput circuit 100;

Echo cancelcircuit 300 carries out echo cancellation process to the sound signal viainput circuit 100;

Output circuit 400 will be via the audio signal output of echo cancellation process.

In the above-mentioned microphone apparatus, describedinput circuit 100, echo cancelcircuit 300 andoutput circuit 400 all can adopt the design of known microphone apparatus corresponding function circuit.For example, describedinput circuit 100 can adopt the design of existing difference input voltage gain.The design form of corresponding difference input, describedoutput circuit 400 can adopt the design of existing difference output equally.

In the above-mentioned microphone apparatus, be provided withpower circuit 200 at the input end ofinput circuit 100 and power separately, thereby avoided microphone apparatus and other functional circuits/equipment common source.Therefore, just can avoid the prior art common source and the power supply that causes disturbs, thereby, the part origin cause of formation that causes noise eliminated.And then, make the noise situations of input end ofinput circuit 100 improve, thereby the overall sound quality of microphone apparatus has obtained raising.

Below by two specific embodiments the utility model microphone apparatus is further illustrated.

With reference to shown in Figure 2, among a kind of embodiment of the utility model microphone apparatus,input circuit 110 is the difference input circuit, and it has differential input end, comprises input anode MIC+ and input negative terminal MIC-.Correspondingly,output circuit 410 is a differential output circuit, and it has difference output end, comprises output plus terminal MIC_P and output negative terminal MIC_N.Power circuit is connected in described input anode MIC+.

Described power circuit comprises: second resistance R 2, the 3rd resistance R 3, the 4th resistance R 4, the 3rd capacitor C 3, the 4th capacitor C 4, the 5th capacitor C 5, the 6th capacitor C 6 and NPN pipe Q1.Wherein, first power end (5V power end) and second source end (MIC_VCCS power end, voltage are 5V, are provided by corresponding power management chip usually) are provided respectively for collector, the emitter of NPN pipe Q1, and base stage links to each other with second end of second resistance R 2; First end of second resistance R 2 links to each other with the 5V power end, and second end links to each other with first end of the 3rd capacitor C 3, the 4th capacitor C 4; The 3rd capacitor C 3,4 parallel connections of the 4th capacitor C, the equal ground connection of second end; First end of the 5th capacitor C 5 links to each other the second end ground connection with the emitter of NPN pipe Q1; First end of the 3rd resistance R 3 links to each other with the MIC_VCCS power end, and second end links to each other with first end of the 4th resistance R 4; Second end of the 4th resistance R 4 links to each other with the input anode MIC+ ofdifference input circuit 110; First end of the 6th capacitor C 6 links to each other with first end of the 4th resistance R 4, the second end ground connection.

In the above-mentioned power circuit, the 4th capacitor C 4 and the 6th capacitor C 6 are the electrochemical capacitor of band polarity, and the 4th resistance R 4 is as the pull-up resistor of the input anode MIC+ ofdifference input circuit 110.

Below the course of work of described power circuit further is analyzed as follows:

Because the base stage of NPN pipe Q1 is connected to collector by second resistance R 2, and collector is connected to the 5V power end, therefore, the voltage that the base stage of NPN pipe Q1 has greater than Vbe makes the triode conducting, thereby at the emitter voltage MIC_VCCS of triode is 5V, at this moment, described power circuit draws power supply by the 3rd resistance R 3, the 4th resistance R 4 on the input anode MIC+ of difference input circuit 110.Each electric capacity in the described power circuit then can carry out filtering to the power supply signal that described power circuit produces, and disturbs to avoid that described input anode MIC+ is produced power supply.

Based on above-mentioned analysis as can be known, above-mentioned power circuit is connected between the power pins (input anode MIC+) and ground of microphone apparatus, has realized the power decoupling function.Thereby, even power end has signal to disturb, its influence to the power pins of microphone apparatus is also less, power pins from described microphone apparatus, the power supply that just can avoid the prior art common source and cause disturbs, thereby, improved the noise situations at microphone apparatus power pins place.Therefore, the overall sound quality of present embodiment microphone apparatus is improved.

By above stated specification as can be known, at the power circuit that the input end increase of microphone apparatus is powered separately, can improve the overall sound quality of microphone apparatus.In order further to improve the overall sound quality of microphone apparatus, the utility model microphone apparatus also provides the another kind of embodiment of optimizing: the prime at echo cancel circuit increases low-pass filter, promptly make low-pass filter be connected in the output of input circuit, make echo cancel circuit be connected in the output of low-pass filter.Because the high-frequency signal of described low-pass filter in can the sound signal that filtering received, thereby realized filtering to the high frequency noise in the sound signal that is received.Thus, the high frequency noise in the sound signal that described echo cancel circuit received is further eliminated.Thereby, finish echo cancellation process at described echo cancel circuit, and via output circuit during with audio signal output, the high frequency noise in the sound signal of described output will improve also.

With reference to shown in Figure 3, among the another kind of embodiment of the utility model microphone apparatus, on the basis of microphone apparatus shown in Figure 2, increased low-pass filter.In the present embodiment, corresponding to 310 concrete chip ports that adopt of echo cancel circuit, the output port of low-pass filter should be corresponding with described chip port.

In the present embodiment, describedecho cancel circuit 310 can adopt for example FM2010 model chip of Fortemedia company.Continuation is with reference to figure 3, and described low-pass filter comprises: the first input resistance R11, the second input resistance R12, first capacitor C 1 and second capacitor C 2.Wherein, first end of the first input resistance R11 is connected in an output terminal of described difference input circuit; First end of first capacitor C 1 is connected in second end of the first input resistance R11, and second end of first capacitor C 1 is connected in an input end ofecho cancel circuit 310; First end of the second input resistance R12 is connected in another output terminal of described difference input circuit; First end of second capacitor C 2 is connected in second end of the second input resistance R12, and second end of second capacitor C 2 is connected in another input end of echo cancelcircuit 310.

Herein, described low-pass filter essence has comprised two low-pass filters, is respectively first low-pass filter that is made of the first input resistance R11 and first capacitor C 1, and second low-pass filter that is made of the second input resistance R12 and second capacitor C 2.

Be to realize low-pass filtering, can carry out corresponding consideration and configuration based on factors such as the frequency range of the sound signal of want filtering and offset error, costs for the first input resistance R11, the second input resistance R12, first capacitor C 1 and second capacitor C 2 resistance value and capacitance separately.

For example, for the first input resistance R11, the second input resistance R12, first capacitor C 1 and second capacitor C 2 separately resistance value and the configuration of capacitance make described first low-pass filter and second low-pass filter all can filtering 50kHz with the sound signal of upper frequency.Suppose, the microphone audio signal that causes importing describeddifference input circuit 110 owing to the reason of aforesaid common source has comprised the noise of 50kHz with upper frequency, then when through described first low-pass filter and second low-pass filter filtering after, to no longer comprise the signal of 50kHz from the sound signal of first low-pass filter and second low-pass filter output, the noise of 50kHz that be filtering also with upper frequency with upper frequency.

In the described low-pass filter, the actual value of the first input resistance R11 and the second input resistance R12 is generally 1M Ω or less than 1M Ω.The selection of resistance value is that between offset error and capacitance is compromise.The first input resistance R11 and the second input resistance R12 are big more, because the input offset voltage that input offset current causes is big more.The offset voltage drift also can increase.And when the first input resistance R11 and the second input resistance R12 selected lower resistance value for use, first capacitor C 1 must use higher input capacitance value to provide identical-3dB turnover, corresponding frequencies F with second capacitor C 2_-3dB=1/ (2 π R1C1), R11=R12 and C1=C2 here.

In addition, in the selection for capacitor,, otherwise should use nonpolar capacitor unless big dc voltage appears in the input end of AC coupling condenser.Therefore, in order to keep size of devices as far as possible little, the value of capacitor C 1 and C2 should be 0.1 μ F or littler.Usually, capacitance is the smaller the better, because such cost can reduce and size can reduce.The rated operational voltage of input coupling capacitor needs enough high puncture to avoid causing because of any contingent high input transient voltage.

Therefore, described in conjunction with preamble, the sound signal of noise that describedecho cancel circuit 410 also will obtain filtering, thereby after describedecho cancel circuit 410 carries out echo cancellation process, the sound signal of exporting via describeddifferential output circuit 410 also will no longer comprise the noise of 50kHz with upper frequency.

Need to prove, more than for the explanation of filtering only for for example, be not frequency range and follow-up corresponding circuit arrangement in order to restriction filtering.

In sum, the utility model microphone apparatus has improved the overall sound quality of microphone apparatus by the power circuit of independent power supply.

Further, before to echo cancellation process, earlier the sound signal of difference input is carried out Filtering Processing, high frequency noise in the described sound signal of filtering, further improve the noise that sound signal comprised that is used to carry out the echo elimination, thereby further improved the overall sound quality of microphone apparatus.

More than disclose many aspects of the present utility model and embodiment, it will be understood by those skilled in the art that others of the present utility model and embodiment.Disclosed many aspects and embodiment just are used to illustrate in the utility model, are not to be to qualification of the present utility model, and real protection domain of the present utility model and spirit should be as the criterion with claims.

Claims (6)

1. microphone apparatus, comprising: input circuit, echo cancel circuit and output circuit is characterized in that also comprise: power circuit, described power circuit is connected in the input end of input circuit, is used for the supplying power for input end to described input circuit.

2. microphone apparatus as claimed in claim 1 is characterized in that, described power circuit comprises: second resistance, the 3rd resistance, the 4th resistance, the 3rd electric capacity, the 4th electric capacity, the 5th electric capacity, the 6th electric capacity and NPN pipe, wherein,

The collector of NPN pipe, emitter connect first power end and second source end respectively, and base stage links to each other with second end of second resistance;

First end of second resistance links to each other with first power end, and second end links to each other with first end of the 3rd electric capacity, the 4th electric capacity;

The 3rd electric capacity, the 4th electric capacity parallel connection, the equal ground connection of second end;

First end of the 5th electric capacity links to each other with the emitter of NPN pipe, the second end ground connection;

First end of the 3rd resistance links to each other with the second source end, and second end links to each other with first end of the 4th resistance;

Second end of the 4th resistance links to each other with the input end of input circuit;

First end of the 6th electric capacity links to each other with first end of the 4th resistance, the second end ground connection.

3. microphone apparatus as claimed in claim 2 is characterized in that, described the 4th electric capacity and the 6th electric capacity are the electrochemical capacitor of band polarity.

4. microphone apparatus as claimed in claim 1 is characterized in that, described input circuit is the difference input circuit; Described output circuit is a differential output circuit.

5. microphone apparatus as claimed in claim 4 is characterized in that, described power circuit comprises: second resistance, the 3rd resistance, the 4th resistance, the 3rd electric capacity, the 4th electric capacity, the 5th electric capacity, the 6th electric capacity and NPN pipe, wherein,

The collector of NPN pipe, emitter connect first power end and second source end respectively, and base stage links to each other with second end of second resistance;

First end of second resistance links to each other with first power end, and second end links to each other with first end of the 3rd electric capacity, the 4th electric capacity;

The 3rd electric capacity, the 4th electric capacity parallel connection, the equal ground connection of second end;

First end of the 5th electric capacity links to each other with the emitter of NPN pipe, the second end ground connection;

First end of the 3rd resistance links to each other with the second source end, and second end links to each other with first end of the 4th resistance;

Second end of the 4th resistance links to each other with the input anode of difference input circuit;

First end of the 6th electric capacity links to each other with first end of the 4th resistance, the second end ground connection.

6. microphone apparatus as claimed in claim 5 is characterized in that, described the 4th electric capacity and the 6th electric capacity are the electrochemical capacitor of band polarity.

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