| 摘要 |
PROBLEM TO BE SOLVED: To provide a stereophonic microphone system that can excellently reduce a touch noise or the like by using a stereophonic microphone. SOLUTION: A microphone 11 is placed opposite to microphones 12, 13. Outputs from the microphones 12, 13 are fed to noninverting terminal of adders 24, 25 respectively through amplifiers 14, 15 and delay circuits 21, 22. Furthermore, output signals from the amplifiers 14, 15 are respectively attenuated by 1/2 attenuators 17, 18 by -6 dB, an adder 19 sums outputs from the attenuators 17, 18 and provides an output of the sum to a noninverting terminal of an adder 20. Furthermore, an output of the microphone 11 is given to an inverting terminal of the adder 20 via an amplifier 16. The adder 20 gives an output resulting from subtracting an output of the amplifier 16 from the sum output of the adder 19 to an adaptive filter 23, which provides an output to noninverting terminals of the adders 24, 25. Then outputs from the adders 24, 25 are given from terminals 29, 30, attenuated at 1/2 attenuators 26, 27 by -6 dB, an adder 28 sums outputs of the attenuators 26, 27 and gives the sum to the adaptive filter 23 as a residual input signal.
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