A simple alias-free QMF system with near-perfect reconstruction

Abstract

This paper presents a design of prototype filters for quadrature mirror filter (QMF) banks. To minimize the value
of reconstruction error for near-perfect reconstruction (NPR), linear optimization has been applied. Variable and
combinational window functions with high side-lobe-fall-off-rate (SLFOR) have been used to design lowpass prototype filters. Use of window functions resulted in simple implementation. High SLFOR of combinational windows reduced the energy leakage due to aliasing from one sub-band to the other. The proposed optimization algorithm takes a few seconds on Pentium processor.