Wireless Telephone Having Multiple Microphones

• US 20090209290A1
• Filed: 04/29/2009
• Published: 08/20/2009
• 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: Bennett, James, Chen, Juin-Hwey
• Granted Patent: US 8,948,416 B2
• Time in Patent Office: Days
• US Class Current: 455/563
• CPC Class Codes: G10L 2021/02165 Two microphones, one receiving mainly the noise signal and the other one mainly the speech signal
• CPC Class Codes: G10L 21/0208 Noise filtering
• CPC Class Codes: H03G 3/32 the control being dependent upon ambient noise level or sound level
• CPC Class Codes: H04M 1/6008 in the transmitter circuit

Abstract

The present invention is directed to 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. The first microphone outputs a first audio signal, the first audio signal comprising 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. An audio-processing engine for use in a telephone, comprising:

a first input configured to receive a first audio signal from a first microphone;

a second input configured to receive a second audio signal from a second microphone; and

a signal-processing module coupled to the first and second inputs and configured to compare an energy of the first audio signal to an energy of the second audio signal in order to discriminate between voice activity and noise in the first audio signal.

2. The audio-processing engine of claim 1, wherein the signal-processing module is further configured to identify time intervals of the first audio signal during which voice activity is present based on the comparison between the energy of the first audio signal and the energy of the second audio signal.

3. The audio-processing engine of claim 1, wherein the signal-processing module is further configured to compare an energy ratio between the first audio signal and the second audio signal.

4. The audio-processing engine of claim 1, wherein the first audio signal and the second audio signal undergo a frequency analysis.

5. The audio-processing engine of claim 4, wherein the frequency analysis comprises a Fast Fourier Transform.

6. The audio-processing engine of claim 1, wherein:

the first input comprises a first analog-to-digital (A/D) converter configured to convert the first audio signal from an analog form to a digital form; and

the second input comprises a second A/D converter configured to convert the second audio signal from an analog form to a digital form.

7. A telephone, comprising:

a first microphone configured to provide a first audio signal;

a second microphone configured to provide a second audio signal; and

a signal-processing module coupled to the first and second microphones and configured to compare an energy of the first audio signal to an energy of the second audio signal in order to discriminate between voice activity and noise in the first audio signal.

8. The telephone of claim 7, wherein the signal-processing module is further configured to identify time intervals of the first audio signal during which voice activity is present based on the comparison between the energy of the first audio signal and the energy of the second audio signal.

9. The telephone of claim 7, wherein the signal-processing module is further configured to compare an energy ratio between the first audio signal and the second audio signal.

10. The telephone of claim 7, wherein the first audio signal and the second audio signal undergo a frequency analysis.

11. The telephone of claim 7, wherein the frequency analysis comprises a Fast Fourier Transform.

12. The telephone of claim 7, further comprising:

a first analog-to-digital (A/D) converter configured to convert the first audio signal from an analog form to a digital form; and

a second A/D converter configured to convert the second audio signal from an analog form to a digital form.

13. A method for processing audio signals in a telephone, comprising:

receiving a first audio signal from a first microphone;

receiving a second audio signal from a second microphone; and

comparing an energy of the first audio signal to an energy of the second audio signal in order to discriminate between voice activity and noise in the first audio signal.

14. The method of claim 13, further comprising:

identifying time intervals of the first audio signal during which voice activity is present based on the comparison between the energy of the first audio signal and the energy of the second audio signal.

15. The method of claim 13, wherein the comparing an energy of the first audio signal to an energy of the second audio signal in order to discriminate between voice activity and noise in the first audio signal comprises:

comparing an energy ratio between the first audio signal and the second audio signal.

16. The method of claim 13, further comprising:

frequency analyzing the first audio signal and the second audio signal.

17. The method of claim 16, wherein the frequency analysis comprises a Fast Fourier Transform.

18. The method of claim 13, further comprising:

converting the first audio signal from an analog form to a digital form; and

converting the second audio signal from an analog form to a digital form.