ECHO CANCELLER DEVICE FOR ACOUSTIC APPLICATION

摘要

PURPOSE:To cancel an echo signal effectively by using a voice switch, to change over an on-microphone with respect to plural microphones and giving a tap coefficient in response to a change in echo path characteristics between a speaker and the plural microphones to an adaptive filter. CONSTITUTION:A microphone switching unit 11 sets a gain to an OFF microphone and the number of ON-microphones and gives its output signal to a subtracter 6 and its component y(k) is cancelled by a pseudo echo signal y(k) from the adaptive filter 5. The filter 5 estimates the echo path characteristics between the speaker 1 and plural microphones, forms characteristics close thereto and generates the signal y(k) from a reception signal x(k) according to the characteristics. A tap coefficient selection circuit 13 always monitors a signal S and if a change exists in the signal S from the unit 11, the circuit 13 revises the tap coefficient of the filter 5 in response to the change. The change is implemented by using tap coefficient memories 14a, 14b,-14N.