Multi-channel adaptive filtering

Details Multi-channel adaptive filtering Multi-channel adaptive filtering

1999-01-22

2002-04-30

Pham, Chi (Department: 2631)

Pulse or digital communications

Equalizers

Automatic

C370S291000, C379S406080

Reexamination Certificate

active

06381272

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to adaptive filtering and more particularly to multi-channel adaptive filtering.
BACKGROUND OF THE INVENTION
Multi-channel adaptive filtering appears in several applications like stereophonic or multi-channel acoustic echo cancellation for audio/video conferencing, active noise control, multi-channel equalization, etc. See, for example, “Acoustic Echo Cancellation System” of Murtaza Ali for which a provisional application Ser. No. 09/261,913 was filed Mar. 3, 1998. This application is incorporated herein by reference. Specially in acoustic echo cancellation and active noise control, the input is not necessarily white (without speech). In such cases, the least mean squares technique has poor convergence rate. On the other hand, the number of filter taps is also very high to allow fast recursive least square (FRLS) like techniques due to high computational complexity (e.g., in multi-channel audio-conferencing, the filter may have thousands of taps). In single channel cases, a class of techniques known as the affine projection algorithm and its fast version have been developed that have low complexity and fast convergence. See Y. Kaneda, M. Tanaka and J. Kojina, “An Adaptive Algorithm with Fast Convergence for Multi-Input Sound Control,”
ACTIVE
-95, pp. 993-1004, Newport Beach, Calif., July 1995; and S. Gay and S. Tavathia, “The Fast Affine Projection Algorithm,”
Proceedings of ICASSP
-95, pp. 3023-3026, 1995. Also see Gay U.S. Pat. No. 5,428,562 incorporated herein by reference.
SUMMARY OF THE INVENTION
In accordance with one embodiment of the present invention a multi-channel filter system for generating an estimated signal for each channel comprises a forward and backward prediction filter generator responsive to multi-channel input signals for generating a single forward prediction vector signal and a corresponding forward error signal and a single backward prediction vector signal and a corresponding backward error signal. An error generator responsive to errors in the estimated signal multiplies the errors by 1-&mgr; for generating error vectors. A pre-filter signal generator responsive to the single forward filter vector signal and corresponding forward error and the single backward filter vector signal and corresponding backward error signal and said error vectors for generating pre-filter coefficients. An adaptive filter output generator coupled to said pre-filter generator and responsive to said pre-filter coefficients and said multi-channel input signals for generating an estimate signal for each channel.


REFERENCES:
patent: 5428562 (1995-06-01), Gay
patent: 5663955 (1997-09-01), Iyengar
patent: 5721772 (1998-02-01), Haneda et al.
patent: 5734715 (1998-03-01), Scalart et al.

Affiliated with

Also associated with

Rating

Multi-channel adaptive filtering does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Multi-channel adaptive filtering, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multi-channel adaptive filtering will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2819140