ACTIVE-NOISE-REDUCTION DEVICE, AND ACTIVE-NOISE-REDUCTION SYSTEM, MOBILE DEVICE AND ACTIVE-NOISE-REDUCTION METHOD WHICH USE SAME

摘要

A reference-signal generation unit for this active-noise-reduction device outputs a vibration and a correlating reference signal to an adaptive filter unit. A filter-coefficient update unit sequentially updates a filter coefficient of the adaptive filter unit, upon receiving an input of an error signal. The error signal is created by a noise and a canceling sound based on the output of the adaptive filter unit. A detection unit detects the filter coefficient of the filter-coefficient update unit, and determines the size of the output of the adaptive filter unit. As a result, the amplitude of the canceling sound is adjusted on the basis of the adaptive-filter-unit output size which was estimated by the detection unit.