Analysis of an adaptive algorithm for feedback cancellation in hearing aids for sinusoidal signals

Analysis of an adaptive algorithm is presented for cancellation of the effect of the feedback path in hearing aids for sinusoidal signals. In this algorithm two LMS type adaptive filters are used. The one is acting as a notch filter for sinusoids. The other is provided for identifying the impulse response of the feedback path by using the signals filtered by the notch filter. The stationary point of the proposed algorithm is shown to be the desired one by considering the causality constraint of the adaptive filter. It is also shown that the stability near this point is guaranteed. Simulation results show the validity of the theoretical findings.