Patents Examined by Shih-Weu Hsieh
  • Patent number: 5796820
    Abstract: The echo canceler includes an N-tap FIR filter and a coefficient controller. Previous filter coefficients which were generated before an estimation error occurrence when the transmitting output signal becomes greater in power than the transmitting input signal are obtained by using only a number S of coefficient correction values and another number (N-1+S) of sequentially received signals. Since the latest (N-1) received signals are stored in (N-1) delay circuits of an N-tap FIR filter, respectively, a relatively small capacity memory may be provided to store the earlier S received signals. The number S is determined so that a time interval determined by the number S of sampling instants is longer than a response time of a double talk detector.
    Type: Grant
    Filed: April 12, 1996
    Date of Patent: August 18, 1998
    Assignee: NEC Corporation
    Inventor: Taisuke Sasada