Design of two-channel equiripple FIR linear-phase quadrature mirror filters using the vector space projection method

A new technique for designing finite impulse response (FIR) quadrature mirror filters (QMFs) is proposed. The approach is based on the vector space projection method (VSPM). Convex constraint sets and their projections that capture the properties of the desired QMFs are given. The proposed approach produces equiripple filters. This method is compared with the classical Johnston's (1980) method and is shown to have certain advantages.