A new method for the design of FIR quadrature mirror-image filter banks

Abstract

A new algebraic method for the design of two-channel finite-duration impulse response quadrature mirror-image filter (FIR QMF) banks is proposed. The method uses a self-convolution technique to reformulate a fourth-order objective function whose minimization lends to the design of QMF banks. It is shown that the reformulated optimization problem can be solved by an iterative technique in which the major part of each iteration is carried out in terms of a closed-form formula. This leads to improved computational efficiency relative to that in several existing design methods. The method is then extended to the design of QMF banks with low reconstruction delay. Two examples are included which show that the proposed design method leads to filter banks with improved performance.