In this paper, an integrated feedback and noise reduction scheme in hearing aids is developed. The technique presented is based on the adaptive feedback cancellation (AFC) and general sidelobe canceller (GSC) with a band-limited adaptation method to better the convergence behavior of both AFC and GSC. The band pass pre-filter is applied to AFC and the band stop pre-filter is applied to GSC to increase the portion of desired signal. An oscillation detector based on the zero crossing rates of the autocorrelation of sub-band signals is designed to calculate the center frequency of the oscillation to make the band-limited adaptation more robust. Convergence analysis and computer simulation illustrate that the proposed algorithm performs effectively to reduce the feedback and noise.
Bibliographic reference. Yao, Miao / Liang, Weiqian (2010): "Integrated feedback and noise reduction algorithm in digital hearing aids via oscillation detection", In INTERSPEECH-2010, 997-1000.