Wireless telephone with uni-directional and omni-directional microphones

• US 20060135085A1
• Filed: 02/24/2005
• Published: 06/22/2006
• Est. Priority Date: 12/22/2004
• Status: Abandoned Application

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Chen, Juin-Hwey
• Application Number:
  US11/065,131
• Publication Number:
  US 20060135085A1
• Time in Patent Office: Days
• US Class Current: 455/79
• 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

Abstract

A wireless telephone having a first microphone and a second microphone and a method for processing audio signal in a wireless telephone having a first microphone and a second microphone. The wireless telephone includes a first microphone, a second microphone, and a signal processor, wherein at least one of the first microphone and the second microphone is a unidirectional microphone. The first microphone outputs a first audio signal that includes a voice component and a background noise component. The second microphone outputs a second audio signal. The signal processor increases a ratio of the voice component to the noise component of the first audio signal based on the content of at least one of the first audio signal and the second audio signal to produce a third audio signal.

Claims

1. A wireless telephone, comprising:

a first microphone that outputs a first audio signal, the first audio signal comprising a voice component and a background noise component;

a second microphone that outputs a second audio signal, wherein at least one of the first microphone and the second microphone is a uni-directional microphone; and

a signal processor that increases a ratio of the voice component to the noise component of the first audio signal based on the content of at least one of the first audio signal and the second audio signal to produce a third audio signal.

2. The wireless telephone of claim 1, wherein the first microphone is a uni-directional microphone and is mounted on the wireless telephone such that the mouth of a user is within an acceptance angle of the first microphone during regular use of the wireless telephone.

3. The wireless telephone of claim 1, wherein the second microphone is a uni-directional microphone and is mounted on the wireless telephone such that the mouth of a user is not within an acceptance angle of the second microphone during regular use of the wireless telephone.

4. The wireless telephone of claim 1, wherein the second microphone is a uni-directional microphone and is mounted on the wireless telephone such that the mouth of a user is within a low-sensitivity angle of the second microphone during regular use of the wireless telephone, wherein the low-sensitivity angle is defined as an angle within which a sensitivity of the second microphone is below a predetermined threshold.

5. The wireless telephone of claim 1, wherein the first microphone is mounted on a first portion of the wireless telephone and the second microphone is mounted on a second portion of the wireless telephone such that the first microphone is closer to the mouth of a user than the second microphone during regular use of the wireless telephone.

6. The wireless telephone of claim 1, wherein the signal processor comprises a background noise cancellation module that receives the first and second audio signals and cancels at least a portion of the background noise component of the first audio signal based on the content of the second audio signal to produce the third audio signal.

7. The wireless telephone of claim 6, wherein the background noise cancellation module comprises:

an adaptive filter that filters the second audio signal; and

an adder that adds the filtered second audio signal to the first audio signal, thereby canceling at least a portion of the background noise component of the first audio signal.

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

9. The wireless telephone of claim 8, wherein the noise suppressor suppresses at least a portion of the residual background noise component by adapting a frequency spectrum corresponding to the third audio signal.

10. The wireless telephone of claim 1, wherein the signal processor comprises a noise suppressor that receives the first and second audio signals and suppresses at least a portion of the background noise component of the first audio signal based on the content of the first audio signal and the second audio signal to produce the third audio signal.

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

a voice activity detector (VAD) that receives the second and third audio signals and detects 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.

12. A method for processing audio signals in a wireless telephone having a first microphone and a second microphone, wherein at least one of the first microphone and the second microphone is a uni-directional microphone, comprising:

outputting a first audio signal from the first microphone, the first audio signal comprising a voice component and a background noise component;

outputting a second audio signal from the second microphone; and

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

13. The method of claim 12, wherein the first microphone is a uni-directional microphone and is mounted on the wireless telephone such that the mouth of a user is within an acceptance angle of the first microphone during regular use of the wireless telephone.

14. The method of claim 12, wherein the second microphone is a uni-directional microphone and is mounted on the wireless telephone such that the mouth of a user is not within an acceptance angle of the second microphone during regular use of the wireless telephone.

15. The method of claim 12, wherein the second microphone is a uni-directional microphone and is mounted on the wireless telephone such that the mouth of a user is within a low-sensitivity angle of the second microphone during regular use of the wireless telephone, wherein the low-sensitivity angle is defined as an angle within which a sensitivity of the second microphone is below a predetermined threshold.

16. The method of claim 12, wherein the increasing step comprises:

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

17. The method of claim 16, wherein canceling at least a portion of the background noise component of the first audio signal based on the content of the second audio signal comprises:

filtering the second audio signal using an adaptive filter; and

adding the filtered second audio signal to the first audio signal, thereby canceling at least a portion of the background noise component of the first audio signal.

18. The method of claim 12, wherein the increasing step comprises:

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

19. The method of claim 16, further comprising:

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

20. The method of claim 19, wherein the suppressing step comprises suppressing at least a portion of the residual background noise component by adapting a frequency spectrum corresponding to the third audio signal.

21. The method of claim 12, 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.

22. A corded telephone, comprising:

a first microphone that outputs a first audio signal, the first audio signal comprising a voice component and a background noise component;

a second microphone that outputs a second audio signal, wherein at least one of the first microphone and the second microphone is a uni-directional microphone; and

a signal processor that increases a ratio of the voice component to the noise component of the first audio signal based on the content of at least one of the first audio signal and the second audio signal to produce a third audio signal.

23. The corded telephone of claim 22, wherein the first microphone is a uni-directional microphone and is mounted on the corded telephone such that the mouth of a user is within an acceptance angle of the first microphone during regular use of the corded telephone.

24. The corded telephone of claim 22, wherein the second microphone is a uni-directional microphone and is mounted on the corded telephone such that the mouth of a user is not within an acceptance angle of the second microphone during regular use of the corded telephone.

25. The corded telephone of claim 22, wherein the second microphone is a uni-directional microphone and is mounted on the corded telephone such that the mouth of a user is within a low-sensitivity angle of the second microphone during regular use of the corded telephone, wherein the low-sensitivity angle is defined as an angle within which a sensitivity of the second microphone is below a predetermined threshold.

26. A headset telephone, comprising:

a headset having a first microphone that outputs a first audio signal, the first audio signal comprising a voice component and a background noise component; and

a handset having a second microphone that outputs a second audio signal, wherein at least one of the first microphone and the second microphone is a uni-directional microphone; and

the handset having a signal processor that receives the first and the second audio signals and increases a ratio of the voice component to the noise component of the first audio signal based on the content of at least one of the first audio signal and the second audio signal to produce a third audio signal.

27. The headset telephone of claim 26, wherein the first microphone is a uni-directional microphone and is mounted on the headset such that the mouth of a user is within an acceptance angle of the first microphone during regular use of the headset.

28. A headset telephone, comprising:

a headset having a first microphone that outputs a first audio signal, the first audio signal comprising a voice component and a background noise component, and the headset having a second microphone that outputs a second audio signal, wherein at least one of the first microphone and the second microphone is a uni-directional microphone; and

the headset having a signal processor that receives the first and the second audio signals and increases a ratio of the voice component to the noise component of the first audio signal based on the content of at least one of the first audio signal and the second audio signal to produce a third audio signal.

29. The headset telephone of claim 28, wherein the first microphone is a uni-directional microphone and is mounted on the headset such that the mouth of a user is within an acceptance angle of the first microphone during regular use of the headset.

30. The headset telephone of claim 28, wherein the second microphone is a uni-directional microphone and is mounted on the headset such that the mouth of a user is not within an acceptance angle of the second microphone during regular use of the headset.

31. The headset telephone of claim 28, wherein the second microphone is a uni-directional microphone and is mounted on the headset such that the mouth of a user is within a low-sensitivity angle of the second microphone during regular use of the headset, wherein the low-sensitivity angle is defined as an angle within which a sensitivity of the second microphone is below a predetermined threshold.

32. The telephone of claim 28, wherein the headset is a BLUETOOTH™

headset.