An oversampling subband adaptive digital filter with rational decimation rations
Hitoshi Kiya, Hirotatsu Yamazaki, Koji Ashihara · Electronics and Communications in Japan (Part III Fundamental Electronic Science) · 1995
Abstract Recent research has been conducted on the subband adaptive filters wherein filter banks are used in the adaptive filters. However, when a complete reconstruction filter bank is used for subband coding, then the effect of aliasing caused by decimation cannot be avoided in subband adaptive digital filter (ADF). One of the solutions to this problem is the oversampling scheme where maximum decimation is not used. In this paper, a filter bank is proposed that allows us to choose arbitrary rational numbers as decimation ratios. As a special case, they include the integral decimation ratio (which may be considered as the general form of filter bank in oversampling scheme). This filter bank simultaneously maintains the advantages of oversampling scheme and makes possible the realization of a subband adaptive system that has a close to maximum decimation ratio with the reduction of filter order. In this paper, the design conditions of the filter bank are first formulated. Based on these design conditions, one method to design the filter banks is proposed. to confirm the effectiveness of this filter bank, the system identification examples are then simulated.