Patent ID: 7796767

Claim:
A howling detector, comprising: a frequency analyzing section for dividing a time signal into a plurality of frequency band signals; a level calculating section for calculating a level of each of the plurality of frequency band signals output from the frequency analyzing section over a time period defining a time progression; a howling detecting section for analyzing the level calculated by the level calculating section and outputting a howling detection signal indicating whether howling is detected or not; a periodic signal detecting section for analyzing the time progression of the level calculated by the level calculating section and outputting a periodic detection signal indicating whether or not the time progression of the level calculated by the level calculating section have periodicity; and a howling deciding section for receiving the howling detection signal and the periodic detection signal, wherein the howling deciding section decides that howling occurs when the howling detection signal indicates howling is detected and the periodic detection signal indicates that the time progression of the level calculated by the level calculating section does not have periodicity.