| 摘要 |
PROBLEM TO BE SOLVED: To provide a single-diaphragm quadratic differential microphone having improved response. SOLUTION: A quadratic differential microphone has a linear differential microphone element 160 set in an enclosure 70. Pairs of front acoustic conduits 80, 90, 100, and 80' to 100' are extended from respective ports 101 and 104 to a front cavity 141 on the front surface of a microphone diaphragm, and pairs of rear acoustic conduits 110, 120, 130, and 110' to 130' are extended from respective ports 102 and 104 to a rear cavity 142 on the rear side surface of the microphone diaphragm. Front ports 101 and 104 and rear ports 102 and 104 are placed approximately on the same line along a sub-axis, and rear ports 102 and 103 are placed between front ports 101 and 104. Acoustic transfer functions from ports 101 to 104 to the diaphragm of the microphone are equal. The response of the microphone is approximately proportional to a space quadratic derivative along the sub-axis of a sample acoustic field.
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