| 摘要 |
PROBLEM TO BE SOLVED: To obtain a noise reducing device in which the number of taps and the circuit scale of an adaptive signal processing circuit can be reduced and the adaptive signal processing circuit hardly performs a malfunction. SOLUTION: This noise reducing device which is provided with the adaptive signal processing circuit for obtaining a false noise signal approximate to a reduction target periodic noise signal from a reference input pulse signal synchronizing with the reduction target periodic noise signal in main input signals, and a subtracter for subtracting the false noise signal from the adaptive signal processing circuit from the main input signal, wherein the adaptive signal processing circuit performs adaptive signal processing such that the subtraction output of the subtracter is fed back to the adaptive signal processing circuit to minimize the noise power of the subtraction output, is provided with a counting means for counting the period of the reference input pulse signal with a prescribed clock. The counting means makes the adaptive signal processing circuit operate in matching the noise timing of the reduction target periodic noise signal, and the adaptive signal processing circuit outputs zero except when it operates. COPYRIGHT: (C)2004,JPO
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