Patent ID: 7925031
Filing Date: 2011-04-12
Classification: H04M,H04R

Abstract:
1. An audio system, comprising: a microphone capturing an audio signal; an audio signal processor; an output transducer; a feedback tone detector which detects a possible feedback tone and a corresponding frequency of the possible feedback tone in the audio system between the output transducer and the microphone; a feedback counteracting unit configured to counteract the feedback; a controller configured to change the phase of the audio signal at a given frequency by a predefined amount of phase change whenever the feedback tone detector detects a possible feedback in the audio system at the given frequency; and a comparator configured to compare the frequency of the detected possible feedback tone before the phase change by the controller, to the frequency of the detected possible feedback tone while the phase of the audio signal is changed by the controller, wherein the controller is further configured to determine whether the possible feedback tone detected by the feedback tone detector is caused by acoustic feedback based on a comparison result of the comparator, the controller is further configured to change the phase of the audio signal back to its original value after the controller completes the determination of whether the possible feedback tone is caused by acoustic feedback.