Title:
ACTIVE NOISE CONTROLLER
Document Type and Number:
Japanese Patent JPH1185166
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To prevent the accumulation of errors without the output of fresh noise with an active noise controller having a function capable of correcting the coefft. of an error route filter during a noise control operation in compliance with the impulse response of the changed error route. SOLUTION: This controller is provided with a differential entire system filter 140 which is provided with an entire system filter for simulating the characteristics over the entire part of the system from a microphone for noise detection to a microphone for error detection and provides the characteristic corresponding to the difference between the two transmission functions given by the entire system filter obtd. with respect to the first and second coeffts. fixed by stopping the coefft. updating of the noise control filter after placing an interval, a differential noise control filter 120 which has the difference of the transmission functions corresponding to the first and second coeffts. as the characteristic and an adaptive filter 130 which is cascade connected to the differential noise control filter. The coefft. of the adaptive filter is so updated that the difference between the output of the differential entire system filter and the output of the adaptive filter is minimized. The coefft. of the error route filter is calculated from the coefft. of the adaptive filter obtd. at the point of the time when the difference described above is minimized.
Inventors:
FUJII KENSAKU
OGA TOSHIRO
OGA TOSHIRO
Application Number:
JP23977797A
Publication Date:
March 30, 1999
Filing Date:
September 04, 1997
Export Citation:
Assignee:
FUJITSU LTD
International Classes:
G10K11/16; G10K11/178; H03H17/02; H03H21/00; (IPC1-7): G10K11/178; G10K11/16; H03H17/02; H03H21/00
Attorney, Agent or Firm:
Shuji Moizumi