(19)
(11) EP 1 074 970 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
09.05.2001 Bulletin 2001/19

(43) Date of publication A2:
07.02.2001 Bulletin 2001/06

(21) Application number: 00122367.6

(22) Date of filing: 02.07.1996
(51) International Patent Classification (IPC)7G10K 11/168, G10K 11/178
(84) Designated Contracting States:
DE FR GB

(30) Priority: 03.07.1995 US 834 P

(62) Application number of the earlier application in accordance with Art. 76 EPC:
96920661.4 / 0836736

(71) Applicant: NATIONAL RESEARCH COUNCIL OF CANADA
Ottawa, Ontario K1A 0R6 (CA)

(72) Inventors:
  • Brammer, Anthony J.
    Gloucester, Ontario K1J 8W9 (CA)
  • Pan, Jianhua
    Gloucester, Ontario K1J 8V8 (CA)

(74) Representative: Skone James, Robert Edmund 
GILL JENNINGS & EVERY Broadgate House 7 Eldon Street
London EC2M 7LH
London EC2M 7LH (GB)

   


(54) Digital feed-forward active noise control system


(57) A method of noise control of an acoustic signal comprising:
  • obtaining a reference signal (X) of the acoustic signal to be controlled, applying an antinoise signal to the acoustic signal so as to control the acoustic signal, obtaining an error signal (E) resulting from the application of the antinoise signal (U) to the acoustic signal, generating the antinoise signal from the reference signal by passing the noise signal through a first filter (33) having controllable filter coefficients, using a simplified model (31) of a signal path from a location (19) of the antinoise signal to a location (21) of the error signal to obtain modified representations of the noise signal, controlling the filter coefficients by processing the error signal and the modified representation of the noise signal and generating a coefficient control signal (35) such as to generate the antinoise signal, and applying the coefficient control signal to the first filter.








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