| 摘要 |
PROBLEM TO BE SOLVED: To perform sufficient amplification during a small amount of volume and to prevent the occurrence of clip when a large amount of volume is inputted. SOLUTION: A microphone device 1 includes a microphone 11 which converts sound pressure into an electrical signal, a variable gain amplifier 21 which amplifies an output signal of the microphone 11 and can adjust an amplification rate, and a control circuit 22 which monitors the level of an output signal VCAout of the variable gain amplifier 21 and controls the amplification rate of the variable gain amplifier 21 so as to prevent the output signal VCAout from clipping in one chip. The control circuit 22 uses comparators Comp1 and Comp2 to monitor the level of the output signal VCAout. COPYRIGHT: (C)2009,JPO&INPIT
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