The design of nonuniform modulated filter banks

In this paper we present an approach to nonuniform filter bank design based on modulated filters and the principle of adjacent channel aliasing cancellation. The approach is a generalization of psuedo QMF designs to nonuniform channel arrangements and the essential idea is to form nonuniform filter banks from uniform sections joined by `transition´ filters. All channel filters are formed by modulating lowpass prototypes. The approach provides a computationally simple method for designing filter banks with large numbers of channels because of the fact that channel filters are modulated from a few lowpass prototypes and because the lowpass prototype designs can be scaled. The technique can be used to produce integer decimation factor designs directly and excellent rational decimation factor designs by combining channel outputs using an inverse polyphase transform