Telephonic communications – Echo cancellation or suppression – Residual echo cancellation
Reexamination Certificate
2005-08-02
2005-08-02
Harold, Jefferey F. (Department: 2644)
Telephonic communications
Echo cancellation or suppression
Residual echo cancellation
C379S406060
Reexamination Certificate
active
06925176
ABSTRACT:
This invention discloses an improvement to a digital Acoustic Echo Control (AEC) in hands-free telephones. It describes an additional adaptive filter referred to as a residual echo filter, which is placed after the usual echo canceller and it is used to efficiently and accurately estimate a residual echo signal b(i) and a system coupling factor β(i), which can be utilized to establish an efficient control for the AEC system and construct the appropriate filters. The invention also describes a control block means performing a joint operation control of the echo canceller, residual echo suppressor and residual echo filter for achieving more consistent echo cancellation results and enhancing output signal quality.
REFERENCES:
patent: 6507653 (2003-01-01), Romesburg
patent: 2003/0219113 (2003-11-01), Bershad et al.
C. Breining et al, Acoustic Echo Control—An Application of Very High-Order Adaptive Filters, IEEE Signal Processing Mag, vol. 16, No. 4, pp. 42-69, Jul. 1999.
S. Haykin, Frequency-Domain and Subband Adaptive Filters, In: Adaptive Filter Theory, Prentice Hall, 4th ed., 2002, Chapters 7.1 and 7.2.
E. Ferrara, Frequency-domain adaptive filtering, In: C. Cowan et al, Adaptive Filters, Prentice Hall, 1985, Chapter 6.
B. Nitsch, A frequency-selective stepfactor control for an adaptive filter algorithm working in the frequency domain, Signal processing, vol. 80, pp. 1733-1746, 2000.
A. Mader et al, Step-Size Control for Acoustic Echo Cancellation Filters—an Overview, Signal Processing, vol. 80, No. 9, pp. 1697-1719, Sep. 2000.
E. Hansler et al, hands-free telephones—joint control of echo cancellation and postfiltering, Signal Processing, vol. 80, No. 11, pp. 2295-2305, 2000.
G. Enzner et al, Partitioned Residual Echo Power Estimation for Frequency-Domain Acoustic Echo Cancellation, etc., Eur. Trans. on Telecomm, vol. 13, No. 2 pp 103-114, Mar. 2002.
G. Glentis et al, Efficient Least Squares Adaptive Algorithms for FIR Transversal Filtering: a unified view, IEEE Signal processing, pp. 13-41, Jul. 1999.
Enzner Gerald
Myllylä Ville
Harold Jefferey F.
Nokia Corporation
LandOfFree
Method for enhancing the acoustic echo cancellation system... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for enhancing the acoustic echo cancellation system..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for enhancing the acoustic echo cancellation system... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3484740