System and method for updating filter coefficients and echo canceller including same

• US 20030053617A1
• Filed: 09/14/2001
• Published: 03/20/2003
• Est. Priority Date: 09/14/2001
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Agere Systems Incorporated (Broadcom, Inc.)
• Inventors: Diethorn, Eric J.
• Granted Patent: US 7,035,397 B2
• Time in Patent Office: Days
• US Class Current: 379/406.01
• CPC Class Codes: H04M 9/082 using echo cancellers echo cancellers per se H04B3/23

Abstract

The present invention provides a system for updating filter coefficients for use with an echo canceller, a related method for updating filter coefficients and an echo canceller including the system or the method. In one embodiment, the echo canceller has a nonadaptive filter and an adaptive filter, the nonadaptive filter having nonadaptive filter coefficients and configured to develop a nonadaptive error signal as a function of the nonadaptive filter coefficients, and the adaptive filter having adaptive filter coefficients and configured to develop an adaptive error signal as a function of the adaptive filter coefficients. In an exemplary embodiment, the system includes a monitoring subsystem configured to monitor a quality of the nonadaptive and adaptive error signals. The system further includes a selection subsystem configured to select one of the nonadaptive and adaptive filter coefficients for use by the nonadaptive filter based on the quality of the nonadaptive and adaptive error signals.

Claims

1. A system for updating filter coefficients for an echo canceller having a nonadaptive filter and an adaptive filter, said nonadaptive filter having nonadaptive filter coefficients and configured to develop a nonadaptive error signal as a function of said nonadaptive filter coefficients, said adaptive filter having adaptive filter coefficients and configured to develop an adaptive error signal as a function of said adaptive filter coefficients, said system, comprising:

a monitoring subsystem configured to monitor a quality of said nonadaptive and adaptive error signals; and

a selection subsystem configured to select one of said nonadaptive and adaptive filter coefficients for use by said nonadaptive filter based on said quality of said nonadaptive and adaptive error signals.

2. The system as recited in claim 1 wherein said selection subsystem is further configured to select said one of said nonadaptive and adaptive filter coefficients based on a comparison of said quality of said adaptive error signal to a reference value and replace said reference value with said adaptive error signal when said quality of said adaptive error signal exceeds said reference value.

3. The system as recited in claim 1 wherein said selection subsystem is further configured to select said one of said nonadaptive and adaptive filter coefficients based on a comparison of said quality of said nonadaptive and adaptive error signals.

4. The system as recited in claim 1 wherein said quality of said nonadaptive error signal is a ratio of said nonadaptive error signal to an outgoing signal and said quality of said adaptive error signal is a ratio of said adaptive error signal to said outgoing signal.

5. The system as recited in claim 1 wherein said monitoring subsystem is further configured to monitor an average quality of said nonadaptive and adaptive error signals as a function of a smoothing parameter.

6. The system as recited in claim 1 wherein said nonadaptive filter is a foreground filter and said adaptive filter is a background filter.

7. The system as recited in claim 1 wherein said quality is represented by a signal strength level.

8. A method of updating filter coefficients for an echo canceller having a nonadaptive filter and an adaptive filter, said nonadaptive filter having nonadaptive filter coefficients and said adaptive filter having adaptive filter coefficients, said method, comprising:

generating a nonadaptive error signal as a function of an incoming signal, an outgoing signal and said nonadaptive filter coefficients;

generating an adaptive error signal as a function of said incoming signal, said outgoing signal and said adaptive filter coefficients;

monitoring a quality of said nonadaptive and adaptive error signals; and

selecting one of said nonadaptive and adaptive filter coefficients for use by said nonadaptive filter based on said quality of said nonadaptive and adaptive error signals.

9. The method as recited in claim 8 wherein said selecting further comprises selecting said one of said nonadaptive and adaptive filter coefficients based on a comparison of said quality of said adaptive error signal to a reference value and replacing said reference value with said adaptive error signal when said quality of said adaptive error signal exceeds said reference value.

10. The method as recited in claim 8 wherein said selecting further comprises selecting said one of said nonadaptive and adaptive filter coefficients based on a comparison of said quality of said nonadaptive and adaptive error signals.

11. The method as recited in claim 8 wherein said quality of said nonadaptive error signal is a ratio of said nonadaptive error signal to said outgoing signal and said quality of said adaptive error signal is a ratio of said adaptive error signal to said outgoing signal.

12. The method as recited in claim 8 wherein said monitoring further includes monitoring an average quality of said nonadaptive and adaptive error signals as a function of a smoothing parameter.

13. The method as recited in claim 8 wherein said nonadaptive filter is a foreground filter and said adaptive filter is a background filter.

14. The method as recited in claim 8 wherein said quality is represented by a signal strength level.

15. A echo canceller, comprising:

a nonadaptive filter having nonadaptive filter coefficients and configured to develop a nonadaptive error signal as a function of an incoming signal, an outgoing signal and said nonadaptive filter coefficients;

an adaptive filter having adaptive filter coefficients and configured to develop an adaptive error signal as a function of said incoming signal, said outgoing signal and said adaptive filter coefficients; and

a system for updating filter coefficients, including;

a monitoring subsystem configured to monitor a quality of said nonadaptive and adaptive error signals, and

a selection subsystem configured to select one of said nonadaptive and adaptive filter coefficients for use by said nonadaptive filter based on said quality of said nonadaptive and adaptive error signals.

16. The echo canceller as recited in claim 15 wherein said selection subsystem is further configured to select said one of said nonadaptive and adaptive filter coefficients based on a comparison of said quality of said adaptive error signal to a reference value and replace said reference value with said adaptive error signal when said quality of said adaptive error signal exceeds said reference value.

17. The echo canceller as recited in claim 15 wherein said selection subsystem is further configured to select said one of said nonadaptive and adaptive filter coefficients based on a comparison of said quality of said nonadaptive and adaptive error signals.

18. The echo canceller as recited in claim 15 wherein said quality of said nonadaptive error signal is a ratio of said nonadaptive error signal to said outgoing signal, and said quality of said adaptive error signal is a ratio of said adaptive error signal to said outgoing signal.

19. The echo canceller as recited in claim 15 wherein said monitoring subsystem is further configured to monitor an average quality of said nonadaptive and adaptive error signals as a function of a smoothing parameter.

20. The echo canceller as recited in claim 15 wherein said nonadaptive filter is a foreground filter and said adaptive filter is a background filter.

21. The echo canceller as recited in claim 15 wherein said quality is represented by a signal strength level.