| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a digital microphone for setting the limited range of an input voltage to an A/D converter with sufficient accuracy corresponding to the full-scale voltage of the A/D converter. Ž<P>SOLUTION: The digital microphone 1 inputs an input signal V12 from a microphone element 2 and outputs an analog signal V14 according to the input signal V12, and includes: a buffer 3 for limiting the analog signal V14 to a predetermined voltage range; an A/D converter 4 for inputting the analog signal V14 from the buffer 3 so as to be converted into a digital signal; and a reference voltage generater 5 for providing a specific voltage V11 which specifies the full-scale voltage of the A/D converter 4 to the A/D converter 4, while providing a reference voltage V13 which specifies the predetermined voltage range of the buffer 3 to the buffer 3. The reference voltage generater 5 generates the reference voltage V13 and the specific voltage V11 based on the output voltage from a common circuit (reference voltage generation circuit 51). Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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