A spectral factorization approach to pseudo-QMF design

A novel approach to the design of M-channel pseudo-quadrature mirror filter (QMF) banks is presented. In this approach, the prototype filter is obtained as a spectral factor of a 2 M^th band filter. This completely eliminates the need for optimization, whereas in conventional pseudo-QMF designs the main computational effort is in optimization of the prototype. The aliasing cancellation constraint is derived such that all the significant aliasing terms are canceled. The overall transfer function of the analysis/synthesis system has an approximately flat magnitude response in the frequency region ε⩽ω⩽(π-ε), where ε depends on the transition bandwidth of the prototype. A design example is included