A Class of Multi-Channel Cosine Modulated IIR Filter Banks

Abstract: This paper presents a class of multi-channel cosine-modulated filter banks satisfying the perfect reconstruction (PR) property using an IIR prototype filter. By imposing a suitable structure on the polyphase filter coefficients, we show that it is possible to greatly simplify the PR condition, while preserving the causality and stability of the system. We derive closed-form expressions for the synthesis filters and also study the numerical stability of the filter bank using frame theoretic bounds. Further, we show that it is possible to implement this filter bank with much lower number of arithmetic operations when compared to FIR filter banks with comparable performance. The filter bank's modular structure also lends itself to efficient VLSI implementation.