| 摘要 |
PROBLEM TO BE SOLVED: To reduce an impact sound without a sense of incongruity by providing an impact sound signal canceling means for outputting a transmitting sound signal by canceling an impact sound signal, based on a collected sound transmitting sound signal and the detected impact sound signal. SOLUTION: Impact sound is collected by microphones 11, 12 during talk, and a micro-amplifier 14 amplifies a transmitting sound signal S obtained by superimposing an impact sound signal Ss by a prescribed gain to output it o an adder 18. At the same time, a micro-amplifier 16 outputs the signal Ss whose phase is inverted to a phase correcting circuit 17, which corrects the delay time of the phase at the signal Ss to output it to the adder 18. The adder 18 adds a transmitting sound signal Sv obtained by superimposing the signal Ss and the signal Ss. The signal Ss obtained by superimposing the signal Sv outputted from the micro-amplifier 14 and the signal Ss outputted from the circuit 17 have voltage values equal to each other and their phases are inverted, so that both of them are surely cancelled.
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