| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To materialize a secondary sound pressure gradient type electret capacitor microphone with simple circuitry, by using two unidirectional capacitor microphone units having identical sensibility and directional frequency characteristics. <P>SOLUTION: By using first and second unidirectional capacitor microphone units U1, U2 having substantially identical sensibility and directional frequency characteristics, resistor elements R3, R4 having an equal resistance are connected to the drain D and source S of the FET Q2 in the second microphone unit U2 placed farther to a sound source, and the drain D of the FET Q2 is connected to the diaphragm 1a of the first microphone unit U1 on the side closer to the sound source via a coupling capacitor C1. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
