Analysis of Adaptive Filters in Feedback Cancellation for Sinusoidal Signals

Abstract—Analysis of coupling effects in adaptive filters is presented for feedback cancellation systems in hearing aids. As the incoming signal, a sum of sinusoids in white noise is assumed in this paper. In the proposed scheme two LMS-type adaptive filters are used. The one is set for identifying the impulse response of the feedback path. The other is associated with frequency estimation. We propose a scheme using the constrained LMS algorithm for the adaptive filter for frequency estimation. The stationary point of the proposed algorithm is shown to be the desired ones. We also show that the simultaneous stability near the stationary point is guaranteed. Simulation results show the validity of the theoretical findings. I