Patent ID: 9123322
Filing Date: 2015-09-01
Classification: G10K,H04R

Abstract:
1. A howling suppression device which reduces a howling component included in an input signal, the howling suppression device comprising: a subtractor which produces an error signal by subtracting, from the input signal, a pseudo feedback signal which is an estimated signal of a feedback signal included in the input signal as the howling component; an adaptive filter which produces the pseudo feedback signal by applying filtering to the error signal, the produced pseudo feedback signal being to be used for a next input signal; and a coefficient update control unit configured to control an update rate of a filter coefficient of the adaptive filter, wherein the coefficient update control unit includes: a level calculation unit configured to calculate a signal level of the input signal; a signal-rising-edge detection unit configured to detect a rising-edge point from which an increase amount of the signal level of the input signal per unit time exceeds a threshold value; a reverberation section detection unit configured to detect a reverberation section which starts at the rising-edge point and ends at a terminal point at which the signal level of the input signal departs from a predetermined range which gradually narrows with time; and an update rate control unit configured to set the update rate in the reverberation section to a first update rate and the update rate in a section other than the reverberation section to a second update rate which is higher than the first update rate, and the adaptive filter updates the filter coefficient for the application of the filtering to the error signal at either the first or second update rate set by the update rate control unit.