| 摘要 |
PROBLEM TO BE SOLVED: To provide a voice communication system that adjusts a received sound volume in response to a surrounding noise level without the need for a separate sound pickup device for the detection of the surrounding noise level. SOLUTION: The voice communication system is provided with a microphone 20 and a speaker 21 and a transmission signal line 22 is led from the microphone 20, and also with a noise detection BEF 23 that receives a signal from the transmission signal line 22, a noise level detector 24 that detects a level of a signal outputted from the noise detection BEF 23, an arithmetic unit 25 that calculates an amplification factor in response to a noise level detected by the noise level detector 24, and an amplifier 27 that amplifies a received signal from an opposite party through a received signal line 26 at an amplification factor calculated by the arithmetic unit 25. The noise detection BEF 23 eliminates only a voice frequency band specific to a talker from a signal sent from the microphone 20 and the received sound volume is adjusted by the amplifier 27 in response to a level detected from the resulting signal by the noise level detector 24.
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