Patent ID: 7697696
Filing Date: 2010-04-13
Classification: H04R

Abstract:
1. An audio amplification apparatus connected to a microphone and a speaker, which constitute a feedback transmission path of an audio signal, the apparatus comprising: an audio amplification circuit which amplifies an audio signal and inputs the amplified audio signal to the speaker; a howling canceller having an adaptive filter which is set with a filter coefficient based on the audio signal input to the speaker and a residual signal so as to simulate the feedback transmission path from the speaker to the microphone such that the adaptive filter processes the audio signal to produce a simulation signal, said residual signal being obtained by subtracting the simulation signal from an input audio signal inputted from the microphone and being fed to the audio amplification circuit; an internal sound source which generates the audio signal and inputs the audio signal to the speaker; and a sound source determination portion which determines whether or not the input audio signal inputted from the microphone contains an external audio signal provided from an external sound source other than the audio signal fed back from the speaker to the microphone and which controls update of the filter coefficient for the adaptive filter in accordance with a result of the determination.