PURPOSE: To provide a noise controller preventing an abnormal sound when the operation of the noise controller is stopped without giving a load to a process of a DSP(digital signal processor) and without enlarging a device scale.
CONSTITUTION: When the operation of the noise controller is stopped, a renewal of a filter coefficient When) (i is a filter coefficient number) deciding a characteristic of an ADF(adaptive digital filter) 106 in the DSP 9 is performed by setting a value of a coefficient (γ) in the following relation Wi(n+1)=γWi(n)+2μe(n)×(n-i) within the range of 0<γ<1. Where, (n) is a sample number in a system, x(n) is a noise signal, e(n) is a synthesis sound wave signal obtained by detecting a synthesis sound between a noise N and a muffle interference sound S outputted from a speaker 102 for canceling the noise N, (μ) is a convergence coefficient and (γ) is a control integer.
TAMURA FUMIO
KATOU SHINJIROU
TARUI NOBUO
TOYOTA MOTOR CORP