Wireless telephone with adaptive microphone array

• US 20060133622A1
• Filed: 05/24/2005
• Published: 06/22/2006
• Est. Priority Date: 12/22/2004
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Chen, Juin-Hwey
• Granted Patent: US 7,983,720 B2
• Time in Patent Office: Days
• US Class Current: 381/92
• CPC Class Codes: H04M 1/03 Constructional features of telephone transmitters or receivers, e.g. telephone hand-sets
• CPC Class Codes: H04M 1/6008 in the transmitter circuit
• CPC Class Codes: H04M 1/6041 Portable telephones adapted for handsfree use
• CPC Class Codes: H04M 9/082 using echo cancellers echo cancellers per se H04B3/23

Abstract

A wireless telephone having an array of microphones and a digital signal processor (DSP) and a method of processing audio signals from a wireless telephone having an array of microphones and a DSP. The wireless telephone includes an array of microphones and a DSP. Each microphone in the array is configured to receive sound waves emanating from the surrounding environment and to generate an audio signal corresponding thereto. The DSP is coupled to the array of microphones. The DSP is configured to receive the audio signals from the array of microphones, to detect a direction of arrival (DOA) of a sound wave emanating from the mouth of a user based on the audio signals and to adaptively combine the audio signals based on the DOA to produce a first audio output signal.

Claims

1. A wireless telephone, comprising:

an array of microphones, each microphone in the array configured to receive sound waves emanating from the surrounding environment and to generate an audio signal corresponding thereto;

a digital signal processor (DSP) coupled to the array of microphones, the DSP configured to receive the audio signals from the array of microphones and to detect a direction of arrival (DOA) of a sound wave emanating from the mouth of a user based on the audio signals and to adaptively combine the audio signals based on the DOA to produce a first audio output signal.

2. The wireless telephone of claim 1,

wherein the DSP is configured to adaptively combine the audio signals based on the DOA to effectively steer a maximum sensitivity angle of the microphone array so that the mouth of the user is within the maximum sensitivity angle, wherein the maximum sensitivity angle is defined as an angle within which a sensitivity of the microphone array is above a predetermined threshold.

3. The wireless telephone of claim 1, further comprising:

a signal processor configured to receive the first audio output signal and a second audio output signal, and increase a ratio of a voice component to a background noise component of the first audio output signal based on the content of at least one of the first audio output signal and the second audio output signal to produce a third audio output signal.

4. The wireless telephone of claim 3, wherein the signal processor comprises a background noise cancellation module that receives the first and second audio output signals and cancels at least a portion of the background noise component of the first audio output signal based on the content of the second audio output signal to produce the third audio output signal.

5. The wireless telephone of claim 4, wherein the signal processor further comprises a noise suppressor that receives the second and third audio output signals and suppresses at least a portion of a residual background noise component of the third audio output signal based on the content of the second audio output signal and the third audio output signal to produce a fourth audio output signal.

6. The wireless telephone of claim 3, wherein the signal processor comprises a noise suppressor that receives the first and second audio output signals and suppresses at least a portion of the background noise component of the first audio output signal based on the content of the first audio output signal and the second audio output signal to produce the third audio output signal.

7. The wireless telephone of claim 3, further comprising:

a voice activity detector (VAD) that receives the second and third audio output signals and detects time intervals in which a voice component is present in the third audio output signal based on the content of the second audio output signal and the third audio output signal.

8. The wireless telephone of claim 3, further comprising:

a second array of microphones, each microphone in the second array of microphones configured to receive sound waves emanating from the surrounding environment and to generate an audio signal corresponding thereto;

a second DSP coupled to the second array of microphones, the second DSP configured to receive the audio signals from the second array of microphones and to detect a DOA of a sound wave emanating from the mouth of a user based on the audio signals and to adaptively combine the audio signals based on the DOA to produce the second audio output signal.

9. The wireless telephone of claim 8,

wherein the second DSP is configured to adaptively combine the audio signals from the second array of microphones based on the DOA to effectively steer a minimum sensitivity angle of the microphone array so that the mouth of the user is within the minimum sensitivity angle, wherein the minimum sensitivity angle is defined as an angle within which a sensitivity of the second microphone array is below a predetermined threshold.

10. A wireless telephone, comprising:

an array of microphones, each microphone in the array configured to receive sound waves emanating from the surrounding environment and to generate an audio signal corresponding thereto;

a digital signal processor (DSP) coupled to the array of microphones, the DSP configured to receive the audio signals from the array of microphones and to detect a direction of arrival (DOA) of a sound wave emanating from a background noise source based on the audio signals and to adaptively combine the audio signals based on the DOA to produce a first audio output signal.

11. The wireless telephone of claim 10, wherein the DSP is configured to adaptively combine the audio signals based on the DOA to effectively steer a minimum sensitivity angle of the microphone array so that the background noise source is within the minimum sensitivity angle, wherein the minimum sensitivity angle is defined as an angle within which a sensitivity of the microphone is below a predetermined threshold.

12. The wireless telephone of claim 10, further comprising:

a second array of microphones, each microphone in the second array of microphones configured to receive sound waves emanating from the surrounding environment and to generate an audio signal corresponding thereto;

a second DSP coupled to the second array of microphones, the second DSP configured to receive the audio signals from the second array of microphones and to detect a DOA of the sound wave emanating from the background noise source based on the audio signals and to adaptively combine the audio signals based on the DOA to produce a second audio output signal.

13. The wireless telephone of claim 12,

wherein the second DSP is configured to adaptively combine the audio signals from the second array of microphones based on the DOA to effectively steer a maximum sensitivity angle of the microphone array so that the background noise source is within the maximum sensitivity angle, wherein the maximum sensitivity angle is defined as an angle within which a sensitivity of the second microphone array is above a predetermined threshold.

14. The wireless telephone of claim 12, further comprising:

a voice activity detector (VAD) that receives the first and second audio output signals and detects time intervals in which a voice component is present in the first audio output signal based on the content of the first audio output signal and the second audio output signal.

15. The wireless telephone of claim 14,

wherein the second DSP is further configured to detect a DOA of a sound wave emanating from the mouth of a user and to dynamically switch between one of

(i) adaptively combining the audio signals from the second array of microphones based on the DOA of the sound wave emanating from the mouth of the user to effectively steer a minimum sensitivity angle of the second microphone array so that the mouth of the user is within the minimum sensitivity angle during time intervals in which a voice component is present in the first audio output signal, wherein the minimum sensitivity angle is defined as an angle within which a sensitivity of the second microphone array is below a predetermined threshold, and

(ii) adaptively combining the audio signals from the second array of microphones based on the DOA of the background noise source to effectively steer a maximum sensitivity angle of the second microphone array so that the background noise source is within the maximum sensitivity angle during time intervals in which a voice component is not present in the first audio output signal, wherein the maximum sensitivity angle is defined as an angle within which a sensitivity of the second microphone array is above a predetermined threshold.

16. A method for processing audio signals in a wireless telephone having a microphone array, comprising:

(a) outputting an audio signal from each microphone in the microphone array;

(b) detecting a direction of arrival (DOA) of a sound wave emanating from the mouth of a user based on the audio signals; and

(c) adaptively combining the audio signals based on the DOA to produce a first audio output signal.

17. The method of claim 16, wherein step (c) comprises:

effectively steering a maximum sensitivity angle of the microphone array so that the mouth of the user is within the maximum sensitivity angle, wherein the maximum sensitivity angle is defined as an angle within which a sensitivity of the microphone array is above a predetermined threshold.

18. The method of claim 16, further comprising:

(d) outputting an audio signal from each microphone in a second microphone array;

(e) adaptively combining the audio signals from the microphones in the second microphone array based on the DOA to produce a second audio output signal.

19. The method of claim 18, wherein step (e) comprises:

effectively steering a minimum sensitivity angle of the second microphone array so that the mouth of the user is within the minimum sensitivity angle, wherein the minimum sensitivity angle is defined as an angle within which a sensitivity of the second microphone array is below a predetermined threshold.

20. The method of claim 18, further comprising:

(f) increasing a ratio of a voice component to a background noise component of the first audio output signal based on the content of at least one of the first audio output signal and the second audio output signal to produce a third audio output signal.

21. The method of claim 20, wherein step (f) comprises:

canceling at least a portion of the background noise component of the first audio output signal based on the content of the second audio output signal to produce the third audio output signal.

22. The method of claim 20, wherein step (f) comprises:

suppressing at least a portion of the background noise component of the first audio output signal based on the content of the first audio output signal and the second audio output signal to produce the third audio output signal.

23. The method of claim 20, further comprising:

detecting time intervals in which a voice component is present in the third audio signal based on the content of the second audio signal and the third audio signal.

24. A method for processing audio signals in a wireless telephone having a microphone array, comprising:

(a) outputting an audio signal from each microphone in the microphone array;

(b) detecting a direction of arrival (DOA) of a sound wave emanating from a background noise source based on the audio signals; and

(c) adaptively combining the audio signals based on the DOA to produce a first audio output signal.

25. The method of claim 24, wherein step (c) comprises:

effectively steering a minimum sensitivity angle of the microphone array so that the background noise source is within the minimum sensitivity angle, wherein the minimum sensitivity angle is defined as an angle within which a sensitivity of the microphone is below a predetermined threshold.

26. The method of claim 24, further comprising:

(d) outputting an audio signal from each microphone in a second microphone array;

(e) adaptively combining the audio signals from the microphones in the second microphone array based on the DOA to produce a second audio output signal.

27. The method of claim 26, wherein step (e) comprises:

effectively steering a maximum sensitivity angle of the second microphone array so that the background noise source is within the maximum sensitivity angle, wherein the maximum sensitivity angle is defined as an angle within which a sensitivity of the second microphone array is above a predetermined threshold.

28. The method of claim 26, further comprising:

(f) detecting time intervals in which a voice component is present in the first audio output signal based on the content of the first audio output signal and the second audio output signal.

29. The method of claim 28, further comprising:

(g) detecting a DOA of a sound wave emanating from the mouth of a user; and

(h) dynamically switching between one of

(1) adaptively combining the audio signals from the second array of microphones based on the DOA of the sound wave emanating from the mouth of the user to effectively steer a minimum sensitivity angle of the second microphone array so that the mouth of the user is within the minimum sensitivity angle during time intervals in which a voice component is present in the first audio output signal, wherein the minimum sensitivity angle is defined as an angle within which a sensitivity of the second microphone array is below a predetermined threshold, and

(2) adaptively combining the audio signals from the second array of microphones based on the DOA of the background noise source to effectively steer a maximum sensitivity angle of the second microphone array so that the background noise source is within the maximum sensitivity angle during time intervals in which a voice component is not present in the first audio output signal, wherein the maximum sensitivity angle is defined as an angle within which a sensitivity of the second microphone array is above a predetermined threshold.