| 摘要 |
PROBLEM TO BE SOLVED: To provide an intercom device easily improving cancel processing performance of speaker sound even when a transmission function of sound waves transmitted from a speaker to a microphone has a frequency characteristic, and preventing howling. SOLUTION: A signal processing part 85 includes: A/D conversion circuits 85c, 85c for making phases of respective audio signals of microphones M1, M2 coincide with each other in a predetermined frequency by delaying A/D conversion timing of the audio signal of the microphone M2; an amplitude adjustment means using an adaptive filter 91 for making the respective output levels of the microphones M1, M2 for speaker sound coincide with each other; an arithmetic part 92 outputting n pieces of audio signals being differences between the respective audio signals of the microphones M1, M2 having passed through the A/D conversion circuits 85c, 85c and the adaptive filter 91; and a signal selection part 93 selecting and outputting a minimum signal from the n pieces of audio signals. COPYRIGHT: (C)2010,JPO&INPIT
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