Subband acoustic echo control using non-critical frequency sampling

Aliasing is often generated in critically decimated subband schemes which can reduce the performance of subband adaptive algorithms. This paper investigates non-critical decimation schemes in which the generation of aliasing in the subbands is avoided by down-sampling the subband signals by a smaller factor than would normally be expected, thereby allowing for analysis filters with finite transition bands. The implementations of two such non-critical schemes are presented, one using FIR and one using IIR filter banks. Simulation results for acoustic echo control using both USASI noise and male speech signals show the non-critical schemes' performance in comparison to critically decimated filter bank approaches.