SUBBAND ECHO CANCELLATION METHOD FOR MULTICHANNEL AUDIO TELECONFERENCE AND ECHO CANCELLER USING THE SAME

In a subband echo cancellation for a multichannel teleconference, received signals x.sub.1 (k), x.sub.2 (k), . . . , x.sub.I (k) of each channel are divided into N subband signals, an echo y(k) picked up by a microphone 16.sub.j after propagation over an echo path is divided into N subband signals y.sub.0 (k), . . . ,y.sub.N-1 (k), and vectors each composed of a time sequence of subband received signals x.sub.1 (k), . . . , x.sub.I (k) are combined for each corresponding subband. The combined vector and an echo cancellation error signal in the corresponding subband are input into an estimation part 19.sub.n, wherein a cross-correlation variation component is extracted. The extracted component is used as an adjustment vector to iteratively adjust the impulse response of an estimated echo path. The combined vector is applied to an estimated echo path 18.sub.n formed by the adjusted value to obtain an echo replica. An echo cancellation error signal e.sub.n (k) is calculated from the echo replica and a subband echo y.sub.n (k).