| 摘要 |
PROBLEM TO BE SOLVED: To provide a howling canceler which attenuates a howling frequency component by a plurality of notch filters wherein, when the number of the howling frequency components is larger than the number of these notch filters, these howling frequency components are effectively canceled. SOLUTION: Assuming that first to fourth notch filters having attenuation characteristics 221 to 224 are allocated to howling frequency components 201 to 204 of "4", a howling coefficient Rk is calculated to these notch filters. As a mean level of the howling frequency components increases, it increases; as a harmonic level thereof increases, it decreases; and as a dispersionσ<SP>2</SP>of the howling frequency components increases, it decreases. Now, if a new howling frequency component 205 is detected, the notch filter having the minimum howling coefficient Rk of the first to fourth notch filters is released, and another notch filter is reallocated to the new howling frequency component 205. COPYRIGHT: (C)2008,JPO&INPIT
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