Audio processing methods and apparatuses utilizing the same

• US 8,731,210 B2
• Filed: 09/21/2009
• Issued: 05/20/2014
• Est. Priority Date: 09/21/2009
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Cheng, Yiou-Wen, Nien, Hsi-Wen
• Primary Examiner(s): Chin, Vivian
• Assistant Examiner(s): HAMID, AMMAR T
• Application Number:
  US12/563,408
• Publication Number:
  US 20110069846A1
• Time in Patent Office: 1,702 Days
• Field of Search: 381/92, 381 97- 99, 381/107, 381/105, 381/56, 381/57, 381/313, 381/321
• US Class Current: 381/92
• CPC Class Codes: G10L 2021/02166 Microphone arrays; Beamforming
• CPC Class Codes: H04R 2410/05 Noise reduction with a separate noise microphone
• CPC Class Codes: H04R 2430/23 Direction finding using a sum-delay beam-former
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407
• CPC Class Codes: H04R 3/02 for preventing acoustic reaction , i.e. acoustic oscillatory feedback specially adapted for hearing aids H04R25/453

Abstract

An audio processing apparatus is provided. A microphone array includes microphone units. Amplifier modules each receives and amplifies an input signal from one microphone unit to generate amplified signals. A compensation module receives adjusted gains corresponding to the amplifier modules, obtains a gain difference between the adjusted gains, and adjusts one amplified signal according to the gain difference to obtain a compensated signal.

Claims

1. An audio processing apparatus, comprising:

a microphone array, comprising a plurality of microphone units;

a plurality of amplifier modules, each receiving and amplifying an input signal from one microphone unit to generate a plurality of amplified signals; and

a compensation module, receiving a plurality of adjusted gains from a plurality of automatic gain control (AGC) units corresponding to the amplifier modules, obtaining a gain difference between the adjusted gains, and adjusting one amplified signal according to the gain difference to obtain a compensated signal.

2. The audio processing apparatus as claimed in claim 1, wherein the compensation module suppresses the amplified signal corresponding to one of the microphone units according to the gain difference.

3. The audio processing apparatus as claimed in claim 1, wherein the amplifier modules comprise:

a plurality of programmable gain amplifiers (PGAs), each receiving the input signal from one corresponding microphone unit, and amplifying the input signal; and

the plurality of automatic gain control (AGC) units, each coupled to one corresponding PGA and adjusting a gain of the corresponding PGA when an amplitude of the corresponding amplified signal is clipped to obtain the adjusted gain.

4. The audio processing apparatus as claimed in claim 3, wherein the compensation module comprises:

a plurality of compensation units, each receiving the amplified signal from one corresponding PGA, and adjusting the amplified signal according to the gain difference; and

a control unit, detecting the gain difference between the adjusted gains and passing the gain difference to one of the compensation units to adjust the amplified signal amplified by one PGA.

5. The audio processing apparatus as claimed in claim 3, wherein the compensation module comprises:

a control unit, detecting and passing the gain difference to one corresponding AGC to further adjust the gain of one corresponding PGA by the gain difference.

6. The audio processing apparatus as claimed in claim 1, further comprising a microphone array signal processing module, processing the compensated signals to obtain a target signal.

7. The audio processing apparatus as claimed in claim 6, further comprising a reverse compensation module reversely adjusting the target signal according to the gain difference to generate an output signal.

8. An audio processing apparatus, comprising:

a first microphone unit;

a first programmable gain amplifier (PGA), receiving a first input signal picked up by the first microphone unit and amplifying the first input signal to generate a first amplified signal;

a first automatic gain control (AGC) unit, coupled to the first PGA and adjusting a first gain of the first PGA when an amplitude of the first amplified signal is clipped;

a second microphone unit;

a second PGA, receiving a second input signal picked up by the second microphone unit and amplifying the second input signal to generate a second amplified signal;

a second AGC unit, coupled to the second PGA and adjusting a second gain of the second PGA when an amplitude of the second amplified signal is clipped; and

a compensation module, coupled to the first and second AGC units, receiving the first and second adjusted gains from the first and second AGC units, obtaining a gain difference between the first and second adjusted gains, and suppressing one of the first and the second input signals or amplified signals in response to the gain difference to obtain a first compensated signal or a second compensated signal.

9. The audio processing apparatus as claimed in claim 8, wherein when the first adjusted gain is greater than the second adjusted gain, the compensation module suppresses the first input or amplified signal by the gain difference.

10. The audio processing apparatus as claimed in claim 8, wherein when the second adjusted gain is greater than the first adjusted gain, the compensation module suppresses the second input or amplified signal by the gain difference.

11. The audio processing apparatus as claimed in claim 8, wherein the first microphone unit is arranged as a main microphone and the second microphone unit is arranged as a supplementary microphone to pick up signals from different directions.

12. The audio processing apparatus as claimed in claim 8, wherein the compensation module comprises:

a first compensation unit, coupled to the first PGA and adjusting the first amplified signal according to a first control signal;

a second compensation unit, coupled to the second PGA and adjusting the second amplified signal according to a second control signal; and

a control unit detecting the gain difference and passing the gain difference to the first or second compensation unit as the first or second control signal.

13. The audio processing apparatus as claimed in claim 12, wherein the control unit subtracts a value of the first adjusted gain from a value of the second adjusted gain to obtain the gain difference, and generates the first control signal so as to instruct the first compensation unit to suppress the first input or amplified signal by the gain difference when the gain difference is a negative value.

14. The audio processing apparatus as claimed in claim 12, wherein the control unit subtracts a value of the first adjusted gain from a value of the second adjusted gain to obtain the gain difference, and generates the second control signal so as to instruct the second compensation unit to suppress the second input or amplified signal by the gain difference when the gain difference is a positive value.

15. The audio processing apparatus as claimed in claim 8, wherein the compensation module comprises:

a control unit, detecting and passing the gain difference to the first AGC unit to further adjust the first gain of the first PGA by the gain difference, or the second AGC unit to further adjust the second gain of the second PGA by the gain difference.

16. The audio processing apparatus as claimed in claim 15, wherein the control unit subtracts a value of the first adjusted gain from a value of the second adjusted gain to obtain the gain difference, and generates a first control signal corresponding to the gain difference so as to instruct the first AGC unit to further suppress the first gain by the gain difference when the gain difference is a negative value.

17. The audio processing apparatus as claimed in claim 15, wherein the control unit subtracts a value of the first adjusted gain from a value of the second adjusted gain to obtain the gain difference, and generates a second control signal corresponding to the gain difference so as to instruct the second AGC unit to further suppress the second gain by the gain difference when the gain difference is a positive value.

18. The audio processing apparatus as claimed in claim 8, further comprising:

a microphone array signal processing module, coupled to the compensation module, and processing the first and the second compensated signals to obtain a target signal; and

a reverse compensation module amplifying the target signal according to the gain difference to generate an output signal.

19. An audio processing method, comprising:

obtaining a gain difference between a first adjusted gain generated by a first automatic gain control (AGC) unit and a second adjusted gain generated by a second AGC unit, wherein the first AGC is arranged to adjust gain of a first programmable gain amplifier (PGA) amplifying signals picked up by a first microphone, and the second AGC is arranged to adjust gain of a second PGA amplifying signals picked up by a second microphone;

suppressing a first signal originally generated by the first microphone by the gain difference when the first adjusted gain is greater than the second adjusted gain; and

suppressing a second signal originally generated by the second microphone by the gain difference when the first adjusted gain is not greater than the second adjusted gain.

20. The method as claimed in claim 19, wherein a first compensation unit is coupled subsequently to the first PGA, a second compensation unit is coupled subsequently to the second PGA, the step of suppression of the first signal comprises suppressing the first signal output from the first PGA by the gain difference via the first compensation unit, and the step of suppression of the second signal comprises suppressing the second signal output from the second PGA by the gain difference via the second compensation unit.

21. The method as claimed in claim 19, wherein the step of suppression of the first signal comprises suppressing the first signal by the gain difference via the first AGC, and the step of suppression of the second signal comprises suppressing the second signal by the gain difference via the second AGC.