Patent ID: 7613529
Filing Date: 2009-11-03
Classification: H04M,H04R

Abstract:
1. A method of reducing acoustic feedback in a system comprising: sequentially converting a buffered acoustic signal to a plurality of sequential frames in a frequency domain, each frame comprising an array of frequency magnitude bins; comparing an old value of a first frequency magnitude bin that is included in a first frame of the sequential frames with a new value of the first frequency magnitude bin that is included in a second frame of the sequential frames; in response to the new value being greater than the old value, adjusting the old value based on the new value and a filter coefficient; identifying the first frequency magnitude bin as a candidate frequency in response to the adjusted old value exceeding a threshold value; testing for a predetermined amount of reduction in a measured amplitude at the candidate frequency by application of a notch filter to the candidate frequency; and bypassing the notch filter if the amount of reduction in a measured amplitude at the candidate frequency is not reduced by the predetermined amount.