Iterative least square design of DC-leakage free cosine modulated filter banks

This paper discusses the design of prototype filter for cosine modulated filter banks. In particular we present a design method to design a prototype filter for DC-leakage free cosine modulated filter banks. The design problem is first formulated as quadratic constrained least square optimization problem. The quadratic constraints are linearized by means of an iterative least-square algorithm that updates the prototype filter using the least-square result obtained in the previous iteration. Simulation results have shown that the proposed design method converges within a few iterations, and high performance cosine modulated filter banks that have large stopband attenuations are obtained with various design specifications for both traditional cosine modulated filter banks and DC-leakage free cosine modulated filter banks.