A frequency-selective stepfactor control for an adaptive filter algorithm working in the frequency domain

Abstract

In this contribution, a frequency-domain adaptive filter combined with a frequency-selective stepfactor control for acoustic echo cancellers is presented. The adaptive filter algorithm uses the overlap and save implementation method to calculate the error signal and the direction in which the filter impulse response should be corrected via the frequency domain with reduced numerical complexity compared to adaptive filters which use the NLMS algorithm. The frequency-selective stepfactor control improves the convergence property of the filter in environments with high background noise levels in the local room. The power spectral density functions of the excitation and the noise signal and the spectral convergence state of the compensator steer the convergence speed in different frequency bands of the adaptive filter. Therefore, the proposed stepfactor control in the frequency domain may outrange stepfactor controls which work in the time domain.