| 摘要 |
PROBLEM TO BE SOLVED: To provide a voice communication device that is easy to develop. SOLUTION: Before permitting speaking using a receiving part 2 and a transmitting part 3, a reference control signal is outputted from a speaker 15 in voice, an amplification factor of a preamplifier 8 is controlled in a control part 12 so that an effective value of an echo signal transmitted from a transmitting part 18 in response to the output is less than a predetermined reference effective value, and speaking is then permitted. COPYRIGHT: (C)2005,JPO&NCIPI
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