| 摘要 |
PROBLEM TO BE SOLVED: To provide a microphone unit capable of acquiring a sound signal with high accuracy by excluding the effect other than that of a microphone shape and using an electromagnetic wave with a high frequency such as light. SOLUTION: The microphone unit 1 includes a pair of electromagnetic wave detectors 2a, 2b provided opposite to a generating source for generating the electromagnetic wave with the high frequency such as light, and a conversion means. The conversion means takes a difference between amounts of the electromagnetic wave detected by the electromagnetic wave detectors 2a, 2b from the light generating source via a gas wherein the difference is caused by density differences (n-Δn and n, and n and n+Δn, or the like) of the gas existing between the generating source and the pair of electromagnetic wave detectors 2a, 2b so as to convert the electromagnetic wave into a 1-bit digital sound signal and to provide an output. COPYRIGHT: (C)2007,JPO&INPIT
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