Telephonic communications – Subscriber line or transmission line interface – Network interface device
Patent
1997-09-19
1999-06-15
Chin, Wellington
Telephonic communications
Subscriber line or transmission line interface
Network interface device
379411, 379 3, 379406, 370289, 370290, 370291, H04M 100
Patent
active
059129662
ABSTRACT:
An echo cancelling system for communication systems. The system includes an adaptive filter that processes the speech signal re-constructed by a voice decoder to generate an echo estimate. The echo estimate is subtracted from the echo containing signal propagating in the communication link to remove or at least reduce the echo corruption. The tap coefficients of the adaptive filter are established on the basis of an error signal that is representative of difference between the echo estimate and the actual echo and on the basis of a signal element that is a component of the re-constructed speech signal. The signal element is highly decorrelated to enable the adaptive filter to converge faster and manifest an improved echo return loss enhancement.
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Chin Wellington
Ferguson Keith
Northern Telecom Limited
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