ACTIVE NOISE REDUCING DEVICE

WIPO Patent Application WO/2006/011380

A1

An active noise reducing device canceling vibration and noise based on the output of an adaptive notch filter (4), wherein when the amount of a variation between the present value and the past value within a specified time of engine pulses inputted into the adaptive notch filter (4) is equal to or higher than a specified value, an engine pulse monitoring means (25) cuts off a switch (26) to stop the output of the adaptive notch filter (4). Before the update speed of a coefficient of adaptive notch filter cannot follow up an engine speed when the engine speed is suddenly changed and the adaptive notch filter (4) is diverged, the output of the adaptive notch filter (4) is stopped to prevent abnormal noise from occurring. Thus, even if the engine pulses are suddenly changed, the abnormal noise outputted from the adaptive notch filter (4) does not reach a user.

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KAN YOICHI
NAKAMURA YOSHIO
ONISHI MASAHIDE
INOUE TOSHIO
TAKAHASHI AKIRA
KOBAYASHI YASUNORI

PCT/JP2005/013127

February 02, 2006

July 15, 2005

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MATSUSHITA ELECTRIC IND CO LTD (JP)
HONDA MOTOR CO LTD (JP)
KAN YOICHI
NAKAMURA YOSHIO
ONISHI MASAHIDE
INOUE TOSHIO
TAKAHASHI AKIRA
KOBAYASHI YASUNORI

B60R11/02; F01N1/00; G10K11/178

JP3449838B2	2003-09-22
JP2000099037A	2000-04-07
US5332061A	1994-07-26
JP2005084500A	2005-03-31
US5581619A	1996-12-03
US5278913A	1994-01-11

See also references of EP 1780082A4

Ishihara, Masaru (Tatsuno Nishi-tenma Bldg. 1-6, Nishi-tenma 3-chom, Kita-ku Osaka-shi Osaka 47, JP)

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