| 摘要 |
PURPOSE:To improve the erasing performance and the talking quality by providing a storage circuit storing a transfer function of plural echo paths and a means combining pseudo echo paths in interlocking with a gain of each microphone. CONSTITUTION:A training signal source 5 is operated at first prior to the start of talking, a gain alpha1 of a gain adjusting circuit 101 is set to '1', gains alpha2-alphan of gain adjusting circuits 102-10n are set to '0', an estimate circuit 6 obtains an estimated sample string of an impulse response of the echo path from a speaker 2 to a microphone 91 and the result is stored in a storage circuit 121. The gain alphaj of a gain adjusting circuit 10j varies in response to a level of an object signal Vj(t) entering each microphone 9j after the start of talking. The gain of the gain adjusting circuit 10j is interlocked equally with the gain of a gain circuit 13j. Thus, in giving an output of an adder 14 as a coefficient of an FIR filter of a pseudo echo path (FIR filter) 7, the pseudo echo path (FIR filter) 7 following momentarily the change in the gains alpha1-alphan of he microphone is obtained.
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