INTEGRATED LATENCY DETECTION AND ECHO CANCELLATION

• US 20090252343A1
• Filed: 04/07/2008
• Published: 10/08/2009
• Est. Priority Date: 04/07/2008
• Status: Active Grant

• Current Assignee: Sony Interactive Entertainment Inc. (Sony Group Corp.)
• Original Assignee: Sony Computer Entertainment Incorporated (Sony Group Corp.)
• Inventors: Mao, Xiadong
• Granted Patent: US 8,503,669 B2
• Time in Patent Office: Days
• US Class Current: 381/66
• CPC Class Codes: H04M 9/082 using echo cancellers echo cancellers per se H04B3/23

Abstract

In an audio system having a microphone, a speaker coupled to a source of audio output, and an echo canceller coupled to the speaker and microphone, latency between the source of audio output and the speaker may be compensated in echo cancellation performed by the echo canceller. The echo canceller may use a reference signal derived from a signal from the source of audio output in echo cancellation. The latency may be compensated by measuring the latency between the signal from the source of audio output and the speaker, determining a delay amount from the latency, delaying the reference signal by the delay amount to produce a delayed reference signal, and using the delayed reference signal as the reference signal in the echo canceller.

Claims

1. In an audio system having a microphone, a speaker coupled to a source of audio output, and an echo canceler coupled to the speaker and microphone, a method for compensating for latency between the source of audio output and the speaker in echo cancellation performed by the echo canceler, wherein the echo canceler uses a reference signal derived from a signal from the source of audio output in echo cancellation, the method comprising:

a) measuring a latency between the signal from the source of audio output and the speaker;

b) determining a delay amount from the latency;

c) delaying the reference signal by the delay amount to produce a delayed reference signal; and

d) using the delayed reference signal as the reference signal in the echo canceler.

2. The method of claim 1, wherein a) includes:

generating a calibration signal,

applying the calibration signal to the speaker;

generating sound from the calibration signal with the speaker;

capturing the sound with the microphone and converting the sound to a microphone signal; and

comparing the calibration signal to the microphone signal.

3. The method of claim 2, wherein applying the calibration signal to the speaker and generating sound from the calibration signal with the speaker include applying the calibration signal to a signal converter coupled between the source of audio output and the speaker.

4. The method of claim 1 wherein the calibration signal is a white noise signal.

5. The method of claim 1 wherein the delay amount is determined by comparing the latency determined in b) to a latency tolerance of the echo canceler.

6. The method of claim 1 wherein d) includes comparing the delayed reference signal with the microphone signal, extracting an echo signal from the microphone signal and subtracting the echo signal from the microphone signal.

7. An audio system operable with a source of audio output, a speaker and a microphone, comprising:

a microphone input configured to receive an audio signal from the microphone;

a speaker output configured to be coupled to the source of audio output;

an echo canceler coupled to the speaker output and the microphone input, wherein the echo canceler is configured to use a reference signal derived from a signal from the source of audio output in echo cancellation,

a latency compensator configured to measure a latency between the signal from the source of audio output and the speaker, determine a delay amount from the latency and delay the reference signal by the delay amount, whereby the echo canceler uses the delayed reference signal as the reference signal for echo cancellation of a signal from the microphone.

8. The audio system of claim 7, further comprising a calibration signal generator coupled to the latency compensator and the speaker output wherein the calibration signal generator is configured to generate a calibration signal and apply the calibration signal to the speaker output.

9. The audio system of claim 8 wherein the calibration signal is a white noise signal.

10. The audio system of claim 8 wherein the speaker output is configured to receive a removable connection to the speaker.

11. The audio system of claim 8 wherein the removable connection is connection for a HDMI or S/PDIF interface.

12. The audio system of claim 7, further comprising a user interface coupled to the latency compensator.

13. The audio system of claim 12 wherein the latency compensator is configured to adjust the delay amount in response to a signal from the user input.

14. An audio system comprising:

a microphone input configured to receive an audio signal from the microphone;

a speaker output configured to be coupled to a source of audio output;

a computer processor coupled to the speaker output and the microphone input; and

computer readable instructions executable by the processor, wherein the computer readable instructions include

echo canceler instructions that, when executed by the processor, use a reference signal derived from a signal from the source of audio output in echo cancellation of a signal from the microphone; and

latency compensation instructions that, when executed by the processor, measure a latency between the signal from the source of audio output and the speaker, determine a delay amount from the latency and delay the reference signal by the delay amount, whereby the echo canceler uses the delayed reference signal as the reference signal for echo cancellation of the signal from the microphone.

15. The audio system of claim 14 wherein the latency compensation instructions include instructions include instructions that, when executed by the processor, generate a calibration signal, apply the calibration signal to a signal converter coupled between the source of audio output and the speaker, capture sound and compare the calibration signal applied to the signal converter to a microphone signal containing sound generated from the calibration signal with the signal converter and the speaker.

16. The audio system of claim 15 wherein the calibration signal is a white noise signal.

17. The audio system of claim 14, further comprising a user interface coupled to the processor.

18. The audio system of claim 17 wherein the compensation instructions are configured to adjust the delay amount in response to a signal from the user input.