Method and system for dual digital microphone processing in an audio CODEC

• US 8,411,603 B2
• Filed: 08/28/2008
• Issued: 04/02/2013
• Est. Priority Date: 06/19/2008
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Kong, Hongwei
• Primary Examiner(s): Ngo, Ricky
• Assistant Examiner(s): SAMUEL, DEWANDA A
• Application Number:
  US12/200,091
• Publication Number:
  US 20090316731A1
• Time in Patent Office: 1,678 Days
• Field of Search: 370/544, 370/290, 370/358, 370/352, 370/354
• US Class Current: 370/290
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

Methods and systems for dual digital microphone processing in an audio CODEC are disclosed and may include demultiplexing one or more received time-multiplexed digital audio signals from one or more digital microphones, and separately processing each of the demultiplexed digital audio signals. The digital microphones may include microelectromechanical (MEMS) microphones. The demultiplexed digital audio signals may be level-converted, downshifted, and/or filtered. The filtering may include a finite impulse response (FIR) filter. A sampling rate of the one or more demultiplexed digital audio signals may be converted by repeating the demultiplexed digital audio signals. Audio beamforming and/or diversity processing may be performed utilizing the digital microphones.

Claims

1. A method for processing audio signals, the method comprising:

demultiplexing received time-multiplexed digital audio signals from one or more digital microphones; and

separately processing said demultiplexed digital audio signals by;

communicating said demultiplexed digital audio signals to a first digital filter circuit and a second digital filter circuit,

determining, using selection modules at said first digital filter circuit and said second digital filter circuit, which of said demultiplexed digital audio signals to select first output signal at said first digital filter circuit and a second output signal at said second digital filter circuit, and

processing the first output signal and the second output signal based on said determination.

2. The method according to claim 1, wherein said one or more digital microphones comprise microelectromechanical (MEMS) microphones.

3. The method according to claim 1, comprising level-converting said demultiplexed digital audio signals.

4. The method according to claim 1, comprising converting a sampling rate of said one or more demultiplexed digital audio signals from at least a first sampling rate to at least a second sampling rate.

5. The method according to claim 4, comprising repeating said demultiplexed digital audio signals for said sampling rate conversion.

6. The method according to claim 1, comprising filtering said demultiplexed digital audio signals.

7. The method according to claim 6, comprising filtering said demultiplexed digital audio signals via a finite impulse response (FIR) filter.

8. The method according to claim 1, comprising downshifting said demultiplexed digital audio signals.

9. The method according to claim 1, comprising audio beamforming utilizing said digital microphones.

10. The method according to claim 1, comprising diversity processing utilizing said digital microphones.

11. A system for processing audio signals, the system comprising one or more circuits, wherein said one or more circuits are configured to:

demultiplex received time-multiplexed digital audio signals from one or more digital microphones; and

separately process each of said demultiplexed digital audio signals by;

communicating said demultiplexed digital audio signals to a first digital filter circuit and a second digital filter, circuit,

determining, using selection modules at said first digital filter circuit and said second digital filter circuit, which of said demultiplexed digital audio signals to select as a first output signal at said first digital filter circuit and a second output signal at said second digital filter circuit, and

processing the first output signal and the second output signal based on said determination.

12. The system according to claim 11, wherein said one or more digital microphones comprise microelectromechanical (MEMS) microphones.

13. The system according to claim 11, wherein said one or more circuits are configured to level-convert said demultiplexed digital audio signals.

14. The system according to claim 11, wherein said one or more circuits are configured to convert a sampling rate of said one or more demultiplexed digital audio signals from at least a first sampling rate to at least a second sampling rate.

15. The system according to claim 14, wherein said one or more circuits are configured to repeat said demultiplexed digital audio signals for said sampling rate conversion.

16. The system according to claim 11, wherein said one or more circuits are configured to filter said demultiplexed digital audio signals.

17. The system according to claim 11, wherein said one or more circuits are configured to downshift said demultipiexed digital audio signals.

18. The system according to claim 11, wherein said one or more circuits are configured for audio beamforming utilizing said digital microphones.

19. The system according to claim 11, wherein said one or more circuits are configured for diversity processing utilizing said digital microphones.

20. A system for processing:

audio signals, said system comprising;

a demultiplexing circuit configured to demultiplex time-multiplexed digital audio signals received from one or more digital microphones into a first digital microphone input signal and a second digital microphone input signal;

a digital filter circuit, coupled to said demultiplexing circuit, configured to;

receive a plurality of received signals, wherein said received signals include a first analog input signal, a second analog input signal, said first digital microphone input signal, and said second digital microphone input signal,

determine one of said plurality of received signals to select as an output signal, and

process said output signal based on said determination;

a loopback circuit configured to;

receive said plurality of received signals, and

filter said plurality of received signals; and

a digital input routing switch, coupled to said loopback circuit and said demultiplexing circuit, configured to route, based on a routing select signal, said time-multiplexed digital audio signals, said first analog input, and said second analog input to said demultiplexing circuit or said loopback circuit.