Bias analysis in continuous adaptation systems for hearing aids

This paper studies analytically the steady-state convergence behavior of adaptive algorithms that approximate the Wiener solution when operating in continuous adaptation to reduce acoustic feedback in hearing aids. A bias is found in the adaptive filter´s estimate of the hearing-aid feedback path when the input signal is not white. Delays in the forward and cancellation paths are shown to reduce the magnitude of the bias. Equations for the bias transfer function are obtained. A discussion about properties of the bias when delays are placed in the forward and cancellation paths follows