WO2006069546A1

WO2006069546A1 - A speech processing approach and device of a wireless terminal

Info

Publication number: WO2006069546A1
Application number: PCT/CN2005/002399
Authority: WO
Inventors: Yongquan He; Zhen Liu
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2004-12-30
Filing date: 2005-12-30
Publication date: 2006-07-06
Also published as: CN100407293C; CN1797544A

Abstract

A speech processing approach of a wireless terminal comprises: receives sound signals in speech direction, and the sound signals are converted into sound pressure signals , and the sound signals in second direction are received, and the sound signals are converted into sound pressure signals at the same time , the sound pressure signals which come from different directions are amplified respectively, and output the signals after the amplified signals are differentiated. A speech processing device of a wireless terminal and a wireless terminal, besides comprising a microphone and a set of analog amplifying circuit, comprise another microphone , another set of analog amplifying circuit and a set of differential circuit , the two microphones convert the received sound signals from different directions into sound pressure signals ,and then the sound pressure signals are inputted to the analog amplifying circuit , the differential circuit performs differential procession on output signals which come from different analog amplifier. Even in strengthen noise environment ,the wireless terminal can largely reduce the noise, and have favourable speech quality .

Description

Method and device for wireless terminal voice processing

The present invention relates to audio processing technology, and more particularly to a method and apparatus for voice processing of a wireless terminal. Background of the invention

At present, the voice processing scheme in the wireless terminal is shown in FIG. 1. FIG. 1 is a circuit diagram of a voice processing of a wireless terminal in the prior art.

In Figure 1, resistor R4 is connected to power supply VCC to provide a bias voltage for the microphone (MIC); resistor R1 = resistor R2, resistor R1 and resistor R2 divide the supply VCC, providing a bias operating voltage for operational amplifier A1, and At this time, the dynamic range of the operational amplifier is the largest; the capacitor C1 is used for blocking, and the capacitor C2 is used for filtering; the amplification factor of the analog amplifier A1 is the ratio of the resistor Rf to the resistor R3, that is, the amplification factor β = Rf/R3. Here, the mounting direction of the MIC in the wireless terminal is that the MIC receiving the sound signal is facing the person, and the sound signal of the vocal direction is received.

According to Fig. 1, the MIC converts the received sound signal into a sound electric signal, that is, a sound pressure signal. Let the sound pressure signal of the MIC output be Vi, Vi include the vocal sound pressure signal and the ambient noise sound pressure signal Vcm, then the output voltage signal after the analog amplifier circuit is:

Vo = ( VI + Vcm ) X Rf/R3 + ( R2/ ( Rl + R2 ) ) VCC

Since R1 = R2, so, '

Vo = β ( VI + Vcm ) + VCC/2 ... ( 1 )

It can be seen from the formula (1) that in the sound pressure signal outputted by the MIC, both the vocal sound pressure signal and the ambient noise sound pressure signal are included, and the prior art does not separate the vocal and environmental noise, but at the same time They are connected to an analog amplifier circuit for amplification and then sent to the audio encoder. As can be seen from FIG. 1, in the prior art, the wireless terminal only uses one MIC to receive the sound signal, and uses an analog amplification circuit to amplify the sound pressure signal output by the MIC and then feeds it into the audio encoder.

In this way, in a noisy environment, such as on a construction site, a workshop, a bus, etc., wireless terminals are used. Because there is no necessary treatment for environmental noise, a large amount of environmental noise is mixed in the human voice, after passing through the existing wireless. After the terminal's voice processing, the receiver will not be able to hear the other party's voice; at the same time, the caller should raise the voice to increase the voice pressure intensity, and make a strong call to ensure that the other party can barely hear it. Summary of the invention

In view of this, the main object of the present invention is to provide a method for voice processing of a wireless terminal, which can reduce the influence of environmental noise on a call and greatly reduce noise; thereby ensuring the quality of the call of the wireless terminal. '

Another object of the present invention is to provide a device for wireless terminal speech processing. The device has a simple structure, which can conveniently reduce the influence of environmental noise on the call, and greatly weaken the ambient noise sound pressure signal, thereby ensuring the wireless terminal well. The amount of call shield.

A third object of the present invention is to provide a wireless terminal capable of conveniently reducing the influence of environmental noise on a call, weakening the ambient noise sound pressure signal, and ensuring the quality of the call of the wireless terminal.

In order to achieve the above object, the technical solution of the present invention is specifically implemented as follows:

A method for voice processing of a wireless terminal provided by the present invention based on the first object includes the following steps:

A. receiving a sound signal from the voice direction and converting the sound signal into a sound pressure signal, simultaneously receiving the sound signal from the other direction and converting the sound signal into a sound pressure signal, respectively, the received sound pressure in different directions The signal is amplified;

B. Differentially process the sound pressure signals in different directions after the amplification process. The magnification of the amplification process in step A of the method is equal.

The differential processing of the method step B includes: performing analog/digital conversion on the sound pressure signals in different directions for digital differential processing.

The other direction described in step A of the method is the direction opposite to the direction of the speech. An apparatus for processing a voice front end of a wireless terminal according to the second aspect of the present invention, the apparatus comprising: a first microphone, configured to receive a sound signal from a voice direction of the wireless terminal and convert the sound signal into a sound pressure signal; An analog amplifying circuit for amplifying the sound pressure signal from the first microphone; wherein the device further comprises:

a second microphone, configured to receive a sound signal from another direction other than a voice direction of the wireless terminal and convert the sound signal into a sound pressure signal;

a second analog amplifying circuit, configured to amplify a sound pressure signal from the second microphone; a differential processing circuit, configured to respectively receive the sound pressure signals outputted by the first analog amplifying circuit and the second analog amplifying circuit, and respectively output the sound pressure signals The road sound pressure signal is differentially processed.

The receiving end of the second microphone of the device faces the opposite end of the receiving end of the first microphone.

The amplification factor of the first analog amplifying circuit of the device is equal to the amplification factor of the second analog amplifying circuit.

The differential processing circuit of the device comprises a first resistor R5, a second resistor R6, a third resistor R7, a fourth resistor R8 and an operational amplifier A3;

One end of the first resistor R5 is connected to the output end of the first analog amplifying circuit, and the other end is simultaneously connected to the inverting input terminal of the operational amplifier A3 and one end of the third resistor R7. The other end of the third resistor R7 is grounded;

One end of the second resistor R6 is connected to the output end of the second analog amplifying circuit, and the other end is simultaneously connected to the non-inverting input terminal of the operational amplifier A3 and one end of the fourth resistor R8, and the other end of the resistor R8 is connected to the operational amplifier A3. On the output; The first resistor R5 and the second resistor R6 have the same resistance; the third resistor R7 and the fourth resistor R8 have the same resistance.

The operational amplifier A3 of the device is a single-supply operational amplifier.

The differential processing circuit of the device is a digital signal processor DSP.

According to a third aspect, a wireless terminal provided by the present invention includes a first microphone in a voice front end processing device of the wireless terminal, configured to receive a sound signal in a voice direction from the wireless terminal and convert the sound signal into a sound pressure signal a first analog amplifying circuit, 'for amplifying a sound pressure signal from the first microphone;

The voice front end processing device of the wireless terminal further includes: i

The receiving end of the second microphone of the wireless terminal faces the opposite end of the receiving end of the first microphone. :

The amplification factor of the first analog amplifying circuit of the wireless terminal is equal to the amplification factor of the second analog amplifying circuit.

The differential processing circuit of the wireless terminal includes a first resistor R5, a second resistor R6, a third resistor R7, a fourth resistor R8, and an operational amplifier A3;

One end of the first resistor R5 is connected to the output end of the first analog amplifying circuit, and the other end is simultaneously connected to the inverting input terminal of the operational amplifier A3 and one end of the third resistor R7, and the other end of the third resistor R7 is grounded;

One end of the second resistor R6 is connected to the output end of the second analog amplifying circuit, and the other end is simultaneously connected to the non-inverting input terminal of the operational amplifier A3 and one end of the fourth 3⁄4 resistor 18, the resistor R8 The other end is connected to the output of the operational amplifier A3;

The first resistor R5 and the second resistor R6 have the same resistance; the third resistor R7 and the fourth resistor R8 have the same resistance.

The operational amplifier A3 of the wireless terminal is a single-supply operational amplifier.

The differential processing circuit of the wireless terminal is a digital signal processor DSP.

It can be seen from the above technical solution that the method of the present invention uses two MICs to receive a sound signal and convert the sound signal into a sound pressure signal, and then outputs one, wherein one MIC mainly outputs a human voice sound pressure signal, and the other MIC mainly outputs an ambient noise sound. Pressing the signal; and respectively amplifying the output vocal sound pressure signal and the ambient noise sound pressure signal, and then performing differential processing on the amplified result and then feeding the audio encoder. The method of the invention improves the quality of the call of the wireless terminal in a noisy environment. The device of the present invention uses two MICs, two sets of analog amplifying circuits and a set of differential processing circuits to process the voice front end of the wireless terminal. The device of the invention has the advantages of simple structure, convenient and flexible realization of the vocal sound pressure signal and the ambient noise sound pressure signal received by the MIC of the wireless terminal, in particular, the quality of the call of the wireless terminal in a strong noise environment. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a prior art wireless terminal voice processing circuit diagram;

2 is a block diagram of a voice processing of a wireless terminal of the present invention;

3 is a schematic structural diagram of a voice processing circuit of a wireless terminal of the present invention. Mode for carrying out the invention

The core idea of the present invention is: using two MICs to receive a sound signal, wherein one MIC mainly receives a human voice signal and converts the signal into a sound pressure signal, which is amplified by an analog amplifier circuit and then input to one end of the differential processing circuit; An MIC mainly receives an ambient noise sound signal and converts the signal into a noise sound pressure signal, and inputs the difference after the analog amplifier circuit The other end of the processing circuit; the differential circuit differentially processes the two input signals: the ambient noise sound pressure signal is greatly weakened, and the output sound pressure signal of the differential processing circuit is mainly a voice sound pressure signal, which is sent to the audio encoder. The sound pressure signal is mainly the vocal sound pressure signal through such processing, which ensures the quality of the call between the two parties.

2 is a block diagram of the voice processing of the wireless terminal of the present invention. As can be seen from FIG. 2, the device of the present invention includes another MIC2 in addition to the existing one MIC1 and one set of analog amplifying circuit 1, and another set of analog amplifying circuit. 2 and a set of differential processing circuits.

'MIC1, for receiving a sound signal and converting the sound signal into a sound pressure signal, and receiving the voice signal mainly in the sound signal; the analog amplifying circuit 1, for amplifying the sound pressure signal from Μϊ;

MIC2, configured to receive a sound signal and convert the sound signal into a sound pressure signal and output the same, and receive the ambient noise sound signal mainly in the sound signal;

An analog amplifying circuit 2 for amplifying a sound pressure signal from the MIC 2;

The differential processing circuit is configured to receive the output sound pressure signals amplified from the analog amplifying circuit 1 and the analog amplifying circuit 2, respectively, and perform differential processing on the two sound pressure signals.

Here, in order to ensure that one of the MIC1 mainly receives the vocal sound signal, and the other MIC2 mainly receives the ambient noise sound signal, two MICs can be used for back-to-back installation, for example, the MIC1 receives the sound signal and the receiver is facing the person. Receiving the sound signal from the vocal direction, which is consistent with the installation direction of the existing MIC, and the MIC2 and the MIC1 are installed back to back, and the receiving end of the MIC2 receiving the sound signal is facing away from the person, that is, the receiving end of the MIC1 and the MIC2 are received. The ends face in opposite directions. Since the directionality of the human voice is strong, the vocal sound signal received by the human MIC1 is stronger, and the vocal sound signal received by the MIC2 on the back side is weaker; and the directionality of the environmental noise is poor, so The ambient noise sounds received by MIC1 and MIC2 are not much different.

Referring now to Figure 2, the method of the present invention is described as follows: First, different sound pressure signals output by MIC1 and MIC2 respectively: Let the sound pressure signal output by MIC1 be Vil, wherein the voice sound pressure signal is VI, the ambient noise sound pressure signal is Vcml; and the sound pressure signal output by MIC2 is Vi2, wherein the vocal sound pressure signal is V2, and the ambient noise sound pressure signal is Vcm2. According to the above MIC1, MIC2 installation method, then, VI >> V2, Vcml «Vcm2.

Then, Vil and Vi2 are respectively amplified. Here, the parameters of the analog amplifying circuit 1 and the analog amplifying circuit 2 can be identical, that is, the amplification ratios of the two circuits are identical, that is, β 1 = β2 = β. After the Vil is amplified by the analog amplifying circuit 1, the sound pressure signal is Vol, and the Vi2 is amplified by the analog amplifying circuit 2, and the sound pressure signal is Vo2.

Then, Vol = β ( VI + Vcml), Vo2 = β ( V2 + Vcm2 )

Finally, the output sound pressure signal Vol of the analog amplifying circuit 1 is input to the inverting input terminal of the differential processing circuit, that is, the + terminal; the output sound pressure signal Vo2 of the analog amplifying circuit 2 is input to the same input terminal of the differential processing circuit, that is, - On the other hand, it is assumed that the amplification factor of the operational amplifier A3 of the differential processing circuit is β 3, then Vo= P3 x (Vol - Vo2),

That is, Vo = p 3 x ( β ( VI + Vcml ) - β ( V2 + Vcm2)),

That is, Vo « β3 χ ( β x VI - β χ V2) « β3 χ β χ VI (2) It can be seen from the formula (2) that after the processing of the method and apparatus of the present invention, the audio code is fed. The sound pressure signal of the device is almost only the sound pressure signal after the vocal sound pressure signal V 1 output by the MIC1 is amplified, and the ambient noise sound pressure signal is largely cancelled after passing through the differential processing circuit, thus ensuring that the wireless terminal is even in the In a strong noise environment, it can also have good call quality, and the caller does not have to raise the trick to talk hard.

In addition, for the differential processing circuit, digital signal processor: (DSP) can also be used to achieve:

The output sound pressure signal Vol of the analog amplifying circuit 1 and the output sound pressure signal Vo2 of the analog amplifying circuit 2 are input to the analog/digital conversion (A/D) port of the DSP, and then the SP pair conversion The subsequent Vol and Vo2 digital signals are digitally differentially processed, and the processing method is also Vo = β 3 X (Vol - Vo2 ), except that the signals here are all digital signals. Finally, the DSP outputs the processed Vo digital signal to the audio encoder after digital/analog conversion (D/A). This processing can better ensure the accuracy of the signal.

It should be noted here that A/D conversion and D/A conversion can be performed by using the conversion function of the DSP itself, or by using a dedicated A/D conversion chip or D/A conversion chip.

3 is a schematic structural diagram of a voice processing circuit of a wireless terminal according to the present invention. As an embodiment, the method and apparatus of the present invention are described in detail below:

Figure 3 includes two microphones, MIC1 and MIC2, where the MIC1 is facing the person, mainly for receiving the vocal sound signal and converting the signal to the adult sound pressure signal. The MIC2 and MIC1 are installed back to back, mainly for receiving. The ambient noise sound signal is converted into a sound pressure signal and output.

Figure 3 also includes an analog amplifying circuit 1 for amplifying the vocal sound pressure signal of the MIC1 output, and an analog amplifying circuit 2 for amplifying the ambient noise sound pressure signal of the MIC2 output. It is assumed that the analog amplifier circuit 1 is identical to the circuit parameters of the analog amplifier circuit 2:

Resistor R14 or R24 is connected to power supply VCC to provide bias voltage for MIC1 or MIC2; resistor R11 - resistor R12, resistor R11 and resistor R12 divide the power supply VCC, provide bias operating voltage for operational amplifier A1, and operate at this time The amplifier has the largest dynamic range; likewise, resistor R21 = resistor R22, resistor R21 and resistor R22 divide the supply VCC to provide a biasing operating voltage for op amp A2, and the op amp has the largest dynamic range.

Capacitor C11 or capacitor C21 is used for blocking, capacitor C12 or capacitor C22 is used for filtering; the amplification factor of analog amplifier circuit 1 is the ratio of resistor Rfl to resistor R13, that is, the amplification factor (3 1 = Rfl/R13; analog amplifier circuit 2 The magnification is the ratio of the resistor Rf2 to the resistor 23, the amplification factor _3 2 = f2/R23 ₀ _ because the two sets of analog amplifier circuit parameters remain dare, then, (31= p2 = Rfl/R13 = RG/R23, where β 1 = β2 = β

In addition, FIG. 3 further includes a differential processing circuit for performing differential processing on the output sound pressure signals from the analog amplifying circuit 1 and the analog amplifying circuit 2, respectively, and after differential processing, retaining the vocal sound pressure signal to cancel the environmental noise. Sound pressure signal.

One end of the resistor R5 in the differential processing circuit receives the output sound pressure signal from the analog amplifying circuit 1, and the other end is simultaneously connected to the inverting input terminal of the operational amplifier A3 and one end of the resistor R7, and the other end of the resistor R7 is grounded;

One end of the resistor R6 receives the sound pressure signal from the analog amplifying circuit 2, and the other end is simultaneously connected to the non-inverting input terminal of the operational amplifier A3 and one end of the resistor R8, and the other end of the R8 is connected to the output terminal of the operational amplifier A3. ;

Among them, the resistor R5 = resistor R6, resistor R7 = resistor R8, the amplification factor of the operational amplifier A3 P 3 = R7 / R5.

Assume that the sound pressure signal output by MIC1' is Vil, where the vocal sound pressure signal is VI, the ambient noise sound pressure signal is Vcml; the MIC2 output sound pressure signal is Vi2, wherein the vocal sound pressure signal is V2, ambient noise sound pressure The signal is Vcm2. Since the MIC1 is facing the person, and the MIC2 and the MIC1 are installed back to back, then,

Input Vil and Vi2 to analog amplifier circuit 1 and analog amplifier circuit 2 respectively, then, Vol = β (Vl+Vcml) + VCC/2, Vo2 = β ( V2 + Vcm2 ) + VCC/2 Finally, the analog amplifier will be amplified. The output voltage Vol of the circuit 1 is input to the inverting input terminal of the operational amplifier A3 of the differential processing circuit, that is, the + terminal; the output voltage Vo2 of the analog amplifying circuit 2 is input to the non-inverting input terminal of the operational amplifier A3 of the differential processing circuit, that is, the - terminal , then

Vo = β 3 X (Vol - Vo2 ),

That is, Vo = β 3 x ( β (VI + Vcml ) + VCC/2 - β ( V2 + Vcm2 ) - VCC/2 L— That is, νο« β3χ ( β xVl - β xV2) « β3 χ β χ VI: Thus, after the processing of the method and the apparatus of the present invention, the sound pressure signal sent to the audio encoder is almost only the vocal sound pressure of the MIC1 output. The signal V 1 is subjected to the amplified sound pressure signal, and the ambient noise signal is largely cancelled after passing through the differential processing circuit, thereby ensuring that the wireless terminal can have good call quality even in a strong noise environment, and the caller does not have to I raised my voice and talked hard.

In order to ensure the accuracy of the differential processing circuit, the operational amplifier A3 is a single-supply operational amplifier, such as the TLV2472 operational amplifier. At the same time, in order to ensure the normal operation of the differential circuit, it is necessary to ensure that the resistor R5 = resistor R6, resistor R7 = resistor R8.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Claims

Claim

A method for voice processing of a wireless terminal, comprising the steps of:

B. Differentially process the sound pressure signals of different directions after the amplification process.

2. The method according to claim 1, wherein the magnification of the amplification process in step A is equal.

3. The method according to claim 1, wherein the differential processing of step B comprises: performing analog/digital conversion on the sound pressure signals in different directions for digital differential processing.

4. The method according to claim 1, wherein the other direction in step A is a direction opposite to the direction of the voice.

5. A device for processing a voice front end of a wireless terminal, the device comprising a first microphone for receiving a sound signal from a voice direction of the wireless terminal and converting the sound signal into a sound pressure signal; a first analog amplification circuit, Amplifying the sound pressure signal from the first microphone; wherein the device further comprises:

6. Apparatus according to claim 5 wherein the received end of the second microphone faces the opposite end of the first microphone.

7. The apparatus according to claim 5, wherein the amplification factor of the first analog amplification circuit is equal to the amplification factor of the second analog amplification circuit.

The device according to claim 5, wherein the differential processing circuit comprises a first resistor R5, a second resistor R6, a third resistor R7, a fourth resistor R8, and an operational amplifier A3;

One end of the second resistor R6 is connected to the output end of the second analog amplifying circuit, the other end is simultaneously connected to the non-inverting input terminal of the operational amplifier A3 and one end of the fourth resistor R8, and the other end of the fourth resistor R8 is connected to the operational amplifier A3. On the output;

9. Apparatus according to claim 8 wherein said operational amplifier A3 is a single supply powered operational amplifier.

10. Apparatus according to claim 5 wherein said differential processing circuit is a digital signal processor DSP.

11. A wireless terminal, comprising: a first microphone in a voice front end processing device of the wireless terminal, configured to receive a sound signal in a voice direction from the wireless terminal and convert the sound signal into a sound pressure signal; a first analog amplification circuit, The sound pressure signal from the first microphone is characterized in that: the voice front end processing device of the wireless terminal further includes:

a second analog amplifying circuit for amplifying a sound pressure signal from the second microphone; The differential processing circuit is configured to respectively receive the sound pressure signals outputted by the first analog amplification circuit and the second analog amplification circuit, and perform differential processing on the two sound pressure signals.

The wireless terminal according to claim 11, wherein the received end of the second microphone faces the opposite end of the first microphone.

The wireless terminal according to claim 11, wherein the amplification factor of the first analog amplifying circuit is equal to the amplification factor of the second analog amplifying circuit.

The wireless terminal according to claim 11, wherein the differential processing circuit comprises a first resistor R5, a second resistor R6, a third resistor R7, a fourth resistor R8, and an operational amplifier A3;

One end of the second resistor R6 is connected to the output end of the second analog amplifying circuit, one end is simultaneously connected to the non-inverting input terminal of the operational amplifier A3 and one end of the fourth resistor R8, and the other end of the fourth resistor R8 is connected to the output of the operational amplifier A3. On the end

The wireless terminal of claim 14, wherein the operational amplifier A3 is a single-supply operational amplifier.

The wireless terminal according to claim 11, wherein the differential processing circuit is a digital signal processor DSP.