| 摘要 |
<p>PURPOSE:To suppress the backward sensitivity nearly zero, by arranging two sets of single directivity microphone units back and forth mutually and synthesizing the output of the back microphone with the output of the front microphone via an attenuation circuit. CONSTITUTION:Since microphone units 1, 2 are arranged inversely, the units 1, 2 output aural signals of almost the same amplitude but opposite phase and they are inputted to a synthesis circuit 3. In this case, the output of the unit 2 arranged backward is applied to the circuit 3 via an attenuator 4. As a result, the response of the unit 1 arranged forward toward 180 deg. and that of the unit 2 arranged backward toward 0 deg. are adjusted equally with the attenuator 4, allowing to obtain a cancelled synthesis signal from the circuit 3.</p> |
