| 摘要 |
<p>PURPOSE:To surely output the sounds to be heard by eliminating effectively the noises. CONSTITUTION:The right and left microphones 1 are provided together with the right and left speakers 3, the right and left amplifiers 2, a 1st arithmetic circuit 10 which calculates and outputs the difference of right and left sound levels based on the outputs of the amplifiers 2, and the right and left noise eliminating circuits 4 and 5 which eliminate the in-phase component out of the output of one of both microphones 1 after input of the output of the other microphone. When the difference of the right and left sound levels is detected with the output of the circuit 10, the in-phase components of both microphone outputs are eliminated Meanwhile a 2nd arithmetic circuit 11 stops the operations of the noise eliminating circuits if the sounds caught by the microphones 1 with the output of the circuit 11 are larger than a prescribed level.</p> |
