ACTIVE NOISE CONTROLLER

WIPO Patent Application WO/1999/053476

A1

An active noise controller for muffling noise by giving forth pseudo-noise having the same amplitude as that of the noise and an opposite phase to that of the noise from a loudspeaker and acoustically superposing the pseudo-noise on the noise. A whole-system filter comprises first and second whole-system filters (141, 143) for simulating characteristics of the whole system including from a noise-sensing microphone to an error-sensing microphone. The first and second whole-system filters (141, 143) are connected in series respectively to second and first noise control filters (142, 144) constituting a noise control filter, thus forming a series combined circuit. The coefficient of the noise control filter is the coefficient of an estimated noise transmission system filter (147) estimated when the difference between the differential output representing the difference between the outputs of the first and second noise control filters (142, 144) when white noise is applied to the series combined circuit and the difference between the responses of the first and second whole-system filters from a differential whole-system filter (146) is minimum.

FUJII KENSAKU (JP)
OHGA JURO (JP)

PCT/JP1999/001984

October 21, 1999

April 14, 1999

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FUJITSU LTD (JP)
FUJII KENSAKU (JP)
OHGA JURO (JP)

G10K11/178; H03H21/00; (IPC1-7): G10K11/178

JPH0635482A	1994-02-10
JPH07219559A	1995-08-18
JPH08179782A	1996-07-12
JPH06230786A	1994-08-19
JPH0732947A	1995-02-03
JPH1185165A	1999-03-30

Moizumi, Shuji (Takanawa 3-chome Minato-ku Tokyo, JP)

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