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Echo canceller for non-linear circuits

  • US 5,796,819 A
  • Filed: 07/24/1996
  • Issued: 08/18/1998
  • Est. Priority Date: 07/24/1996
  • Status: Expired due to Term
First Claim
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1. In an audio circuit comprising a microphone and a loudspeaker, said microphone detecting a speech signal from a near-end user, said loudspeaker receiving a far-end speech signal and generating a corresponding echo signal that is also detected by said microphone, a method of cancelling the echo signal comprising the steps of:

  • providing at least one other microphone in said audio circuit for detecting said echo signal, said at least one other microphone also detecting said near-end speech signal;

    estimating a plurality of acoustic transfer functions in a plurality of adaptive filters each having a plurality of coefficients, at least one of said adaptive filters using the far-end speech signal as a reference signal for adjusting its coefficients;

    filtering the outputs of one or more of said microphones using the coefficients of one or more of said adaptive filters; and

    combining the filtered and any unfiltered microphone outputs so as to substantially cancel said echo signal while substantially preserving said near-end speech signal.

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