Telephonic communications – Echo cancellation or suppression
Patent
1995-02-24
1997-02-04
Brown, Thomas W.
Telephonic communications
Echo cancellation or suppression
379388, 379410, 379411, H04M 908
Patent
active
056007183
ABSTRACT:
In an audio system, a loudspeaker responds to an input signal producing a sound pressure wave having a linear component, which is linear function of the input signal, and an undesired non-linear component, which is a non-linear function of the input signal. Accordingly, it is desirable to reduce the non-linear component of the output sound pressure wave. An adaptive precompensating audio system for reducing this non-linear component includes a loudspeaker for producing a sound pressure wave and a precompensating filter for precompensating an input signal representative of the desired sound pressure wave. In addition, a microphone may be used to convert the resulting sound pressure wave into a sound signal and a precompensating filter modifier may be used to modify the precompensating filter in response to the sound signal. Preferably, the precompensating filter transforms the input signal using an inverse of an estimated transfer function for the loudspeaker.
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Dent Paul W.
Johnsen Ronald J.
Rasmusson Jim A. J.
Brown Thomas W.
Ericsson Inc.
Saint-Surin Jacques M.
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