A Family of IIR Two-Band Orthonormal QMF Filter Banks

Abstract

The design and characteristics of orthonormal two-band QMF filter banks, with perfect reconstruction and linear phase properties, are considered in this paper. The analysis and synthesis filter banks are implemented using allpass filters. Filters in the synthesis bank are anticausal and unstable filters and the block processing technique and an appropriate causal filter are applied for their real time application. The generated filter banks characteristics and the finite block length influence of the block processing technique applied for anticausal filtering are illustrated for a rectangular input signal case. The corresponding wavelet and scaling functions, generated after five iterations of the analysis bank in a lowpass branch, are shown.