On perfect-reconstruction allpass-based cosine-modulated IIR filter banks

In this paper, we consider the theory and design of the cosine-modulated infinite-impulse-response (IIR) perfect reconstruction (PR) filter banks. The analysis and synthesis filters are cosine-modulated versions of prototype filter. Moreover, the polyphase components of the prototype filter are allpass filters. Necessary and sufficient conditions on the allpass filters are derived such that the filter bank is a PR system. The proposed filter bank is the only known IIR cosine-modulated filter bank. A design procedure for the proposed filter bank is outlined and design examples are given to demonstrate the theory.>