Design of paraunitary oversampled cosine-modulated filter banks

In this paper we derive perfect reconstruction (PR) conditions for oversampled cosine-modulated filter banks. The results can be regarded as a generalization of the known work for critical subsampling. We show that in the oversampled case we gain some additional degree of freedom, which can be exploited in the filter design process. This leads to PR prototypes with stopband attenuations being much higher than in the critically subsampled PR case. The filters designed as PR filters for the oversampled case can also serve as prototypes for critically subsampled cosine-modulated pseudo QMF banks