An efficient approach for the design of nearly perfect-reconstruction QMF banks

In this work, an approach for the design of a class of quadrature mirror filter (QMF) banks is presented based on a combination of IIR analysis filters and FIR synthesis filters. By examining the phase property of the all-pass based analysis filter, a condition on the synthesis part for a perfect reconstruction is established, making it possible to realize a nearly perfect-reconstruction (PR) filter bank by using a nonlinear-phase FIR synthesis filter. The distinct feature of the proposed mixed IIR/FIR filter bank is that it enjoys both a small reconstruction error and a low design and implementation complexity.