Telephonic communications – Subscriber line or transmission line interface – Network interface device
Patent
1994-11-08
1996-06-11
Hofsass, Jeffery
Telephonic communications
Subscriber line or transmission line interface
Network interface device
379410, 379406, 370 321, H04M 908, H04B 323
Patent
active
055264263
ABSTRACT:
A multi-block frequency-domain adaptive filter in an acoustic echo canceller as applied to a full-duplex speakerphone includes convolving a received reference signal with a linear room model to generate an echo free signal for transmission which, in turn, is used to adapt the coefficients of the room model. The frequency-domain estimated echo response is transformed into the time-domain to generate an approximated time-domain echo signal which is subtracted from a microphone signal containing a desired intelligence signal and the actual echo to produce an outgoing signal. The outgoing signal serves as an error signal used to adapt the filter. In the preferred embodiment, a weighting means adjusts the frequency-domain room coefficients during the convolution operation. In another embodiment, a weighting means adjusts the frequency-domain room coefficients by adjusting the correlation terms during adaptation of the frequency-domain room coefficients. A constraint operation operating in conjunction with a constraint scheduler is employed to selectively constrain certain ones of the frequency-domain room coefficients. This offers the benefits of a fully constrained adaptation method, while effectively minimizing the necessary computations of such a constraint operation.
REFERENCES:
patent: 4633046 (1986-12-01), Kitayama et al.
patent: 4636586 (1987-01-01), Schiff
patent: 4658426 (1987-04-01), Chabries et al.
patent: 4807173 (1989-02-01), Sommen et al.
patent: 4903247 (1990-02-01), Van Gerwen et al.
patent: 4951269 (1990-08-01), Amano et al.
patent: 5117418 (1992-05-01), Chaffee et al.
patent: 5278900 (1994-01-01), Van Gerwen et al.
patent: 5416845 (1995-05-01), Shen
patent: 5463618 (1995-10-01), Furukawa et al.
patent: 5477534 (1995-12-01), Kusano
Prado, J. et al., "Frequency-Domain Adaptive Filtering with Applications to Acoustic Echo Cancellation," Apr. 26, 1994, pp. 1-11.
Borrallo, J. M. P. et al., "On the Implementation of a Partitioned Block Frequency Domain Adaptive Filter (PBFDAF) for Long Acoustic Echo Cancellation," Signal Processing, vol. 27, No. 3, Jun. 1992, pp. 301-315.
Asharif, M. F. et al., "Frequency Bin Adaptive Filtering (FBAF) Algorithm and Its Application to Acoustic Echo Cancelling," IEICE Transactions, vol. E 74, No. 8, Aug. 1991, pp. 2276-2282.
Soo, J. et al., "Multidelay Block Frequency Domain Adaptive Filter," IEEE Transactions on Acoustics, Speech, and Signal Processing, vol. 38, No. 2, Feb. 1990, pp. 373-376.
Clark, G. A. et al., "A Unified Approach to Time--and Frequency-Domain Realization of FIR Adaptive Digital Filters," IEEE Transactions on Acoustics, Speech, and Signal Processing, vol. ASSP-31, No. 5, Oct. 1983, pp. 1073-1083.
Hofsass Jeffery
Signalworks
Weaver Scott L.
LandOfFree
System and method for an efficiently constrained frequency-domai does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System and method for an efficiently constrained frequency-domai, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System and method for an efficiently constrained frequency-domai will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-360161