Patent ID: 8958568
Filing Date: 2015-02-17
Classification: G10K

Abstract:
1. A feedback active noise control apparatus for performing a sound cancellation control on road noise having a prescribed bandwidth, the active noise control apparatus, comprising: a canceling sound generator for generating a canceling sound for canceling noise; an error signal detector for detecting an error signal based on a difference between the noise and the canceling sound; a waveform data table for storing predetermined waveform data; a reference signal generator for generating a reference signal based on a frequency of the noise by successively reading the predetermined waveform data from the waveform data table; a first adaptive filter for multiplying the reference signal by a filter coefficient to generate a control signal; a subtractor for subtracting the control signal from the error signal to generate a corrected error signal; a filter coefficient updater for sequentially updating the filter coefficient of the first adaptive filter to minimize the corrected error signal, based on the reference signal and the corrected error signal; an adjustment reference signal generator for generating an adjustment reference signal based on the sound transfer characteristics from the canceling sound generator to the error signal detector by successively reading waveform data from the waveform data table from a read position, which is shifted a prescribed quantity from a read position used for reading the reference signal from the waveform data, such that a phase of the canceling sound is opposite in phase to the road noise; and a second adaptive filter for multiplying the adjustment reference signal by the filter coefficient to generate a canceling signal, wherein the canceling sound generator generates the canceling sound based on the canceling signal.