| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive speech communication device capable of preventing howling from occurring by canceling a sound component generated by a speaker from a transmission signal over a wide frequency band. SOLUTION: A/D converting circuits 311 to 31n A/D-convert a sound signal from a microphone M2 after lapse of delay times Td1 to Tdn to sound waves of frequency bands G1 to Gn from timing that an A/D converting circuit 301 A/D-converts a sound signal from a microphone M1, make attenuating circuits 341 to 34n match output levels of the microphones M1 and M2 with each other by predetermined frequency bands, and an arithmetic circuit 38a outputs the difference between the sound signals of the microphones M1 and M2. COPYRIGHT: (C)2008,JPO&INPIT
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