MULTI-CHANNEL ECHO CANCEL METHOD, MULTI-CHANNEL SOUND TRANSFER METHOD, STEREO ECHO CANCELLER, STEREO SOUND TRANSMISSION APPARATUS, AND TRANSFER FUNCTION CALCULATION APPARATUS

摘要

PROBLEM TO BE SOLVED: To solve the problem of an indefinite coefficient in the echo cancel technique of a multichannel sound signal. SOLUTION: Stereo sound signals are reproduced directly from loudspeakers SP(L) and SP(R). By using a sum signal and a difference signal of the stereo sound signal as a reference signal and according to a cross spectrum calculation of the reference signal with a microphone-collected sound signal, calculation is performed to obtain the transfer functions of four sound transfer systems between the loudspeakers SP(L), SP(R) and microphones MC(L), MC(R). The transfer functions obtained are subjected to inverse Fourier transformation to obtain impulse response, which are set in filter means 40-1 to 40-4 to create echo cancel signals and perform echo canceling.