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

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