Linear phase oversampled filter banks

This paper introduces a factorization for the design of oversampled filter banks with linear phase and complex-valued coefficients. Our approach is based on the design of rectangular paraunitary polyphase matrices and gives a general formulation for perfect reconstruction filter banks with uniform sampling in the subbands, critically sampled or oversampled, and linear phase filters with real- or complex-valued coefficients. By using a framework that is not restricted to modulation of a prototype window, as in oversampled modulated filter banks, we are able to increase the design freedom and to allow the design of non uniform bandwidth oversampled filter banks.