| 摘要 |
PURPOSE:To faithfully reproduce an input signal without being affected by circumstances by controlling a control filter by the input signal and the feed- back of really heard reproduced sounds. CONSTITUTION:Arbitrary frequency signals generated by an oscillator 20 are converted into analog signals by a D/A converter 15, in the initial value setting mode of a control filter coefficient, amplified by a power amplifier 16, and then reproduced by a speaker 17. The reproduced sounds are affected by echo sounds, turned into signals by a microphone 18, amplified by a microphone amplifier 21, and converted into digital signals by an A/D converting circuit 22. The output signals of the A/D converting circuit 22 are compared with those of the oscillator 20 by a comparator 23, the signals affected by the echo sounds are taken out, and stored and set in a control filter coefficient setting equipment 24 as the coefficient of the frequency. After setting, the reproduction mode of the input signals is designated. |
