Telephonic communications – Diagnostic testing – malfunction indication – or electrical... – Of hybrid or echo suppressor or canceller
Patent
1994-01-07
1995-12-12
Chin, Stephn
Telephonic communications
Diagnostic testing, malfunction indication, or electrical...
Of hybrid or echo suppressor or canceller
379406, 379410, 379411, H04M 124, H04M 900, H04M 908
Patent
active
054757312
ABSTRACT:
An echo-canceling system and method uses an echo estimate to modify the error signal which is obtained by the difference between an echo signal and the echo estimate. The modified error signal, rather than the error signal itself, is transmitted. By using the echo estimate as a parameter for modifying the error signal, improved hands-free performance may be obtained in a vehicular radiotelephone, such as a cellular telephone. Preferably, modification of the electrical error signal is performed by a center clipper which removes a portion of the electrical error signal which is below a variable threshold, wherein the variable threshold is determined by the echo estimate electrical signal. The variable threshold may be produced from the echo estimate electrical signal using an envelope detector.
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Chin Stephn
Ericsson Inc.
Shankar Vijay
LandOfFree
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