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1. (WO2001005053) FAST LINE ECHO CANCELLATION

Pub. No.:    WO/2001/005053    International Application No.:    PCT/US2000/017943
Publication Date: Fri Jan 19 00:59:59 CET 2001 International Filing Date: Fri Jun 30 01:59:59 CEST 2000
IPC: H04B 3/23
Applicants: DSP SOFTWARE ENGINEERING, INC.
Inventors: TANRIKULU, Oguz
Title: FAST LINE ECHO CANCELLATION
Abstract:
The present invention is a method and apparatus for estimating the bulk delay and span associated with an echo signal on a telephone line carrying a proximal signal and an echo signal. A baseline solution is to use the echo canceller itself to estimate the bulk-delay. After achieving a reasonable level of echo cancellation, the bulk-delay and the echo-span are estimated from the adaptive coefficients, followed by an enhanced mode of operation using the estimated parameters. Alternatively, for longer, unknown bulk delays, a subband adaptive system is used to estimate the bulk-delay and echo-span. The subband adaptive echo canceller outputs the set of subband adaptive coefficients to a full-band echo canceller after achieving a reasonable level of convergence.