FEEDBACK TYPE ACTIVE NOISE CONTROL DEVICE

摘要

PROBLEM TO BE SOLVED: To realize an update circuit of a noise control filter coefficient having a feedback control filter simulating a characteristics of a feedback path to a microphone for detecting a noise connected to an input side of a noise control filter synthesizing the simulation noise through a loudspeaker by sending out a simulation noise of a noise desired to suppress. SOLUTION: This device is provided with an inverse filter constitution circuit 260 and a system identifying circuit 120 updating the coefficient so that difference between an output of a noise control filter or a filter 121 and an output of an adaptive filter 123 connected to the filter 122 is made the minimum. Further, in the system identifying circuit 120, calculation is repeated as a coefficient of the adaptive filter 123 by constituting a numerator in the first filter 121 and a denominator in the second filter 122 of a fraction constituting a ratio of a transfer functions expressing a generation process of a noise to be controlled obtained from simultaneous equations to a transfer function of the feedback path identified previously by the system identifying circuit 120.