Echo canceler and echo path estimating method

摘要

PCT No. PCT/JP95/00866 Sec. 371 Date Jan. 16, 1996 Sec. 102(e) Date Jan. 16, 1996 PCT Filed May 2, 1995 PCT Pub. No. WO95/31052 PCT Pub. Date Nov. 16, 1995The present invention relates to an echo canceler for training an echo path estimation without providing a hindrance to a speech. The echo canceler of the present invention includes a pseudo noise generator for generating a certain pseudo noise. This pseudo noise is forcibly supplied to a transmission line for transmitting a far-end talker's voice. Here, in the case where the far-end talker's transmitting speech level is faint or the far-end talker is in a speechless condition, a certain correlation is established between the pseudo noise and a signal of the transmission line for transmitting the near-end talker's voice. Based on such a correlation as just mentioned, a coefficient for generating an echo replica is calculated. Therefore, a training for estimating an echo path is performed based on the pseudo noise and without depending on the far-end talker's voice, thereby enabling to generate an appropriate echo replica.