| 摘要 |
PROBLEM TO BE SOLVED: To accurately reduce a cyclical noise signal component from an input audio signal S1. SOLUTION: In an adaptation processing part 20, a pseudo noise signal S6 similar to a cyclical noise signal component is generated by a pseudo noise signal generation part 23, the pseudo noise signal S6 is subtracted from an input audio signal S1 to generate a noise reduction signal S2 by an adder 21, the pseudo noise signal S6 is fed back to the pseudo noise signal generation part 23 to be converged so as to be adaptively similar to the cyclical noise signal component, and when the amplitude of the noise reduction signal S2 fluctuates over a threshold value, the amplitude of the noise reduction signal S2 is controlled to be equal to the threshold value or less by an amplitude control part 22 between the adder 21 and the pseudo noise signal generation part 23. Thus, an increase in amplitude of the pseudo noise signal S6 is reduced by asuming the greatly changed amplitude of the noise reduction signal S2 as a cyclical noise signal component, and the cyclical noise signal component is accurately reduced from the input audio signal S1. COPYRIGHT: (C)2008,JPO&INPIT
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