A two-band linear-phase QMF lattice with an improved robustness to coefficient quantization

Abstract

In this paper we examine the design problem of a new lattice structure for two-band perfect reconstruction filter banks with linear phase analysis and synthesis filters. The aim is to provide sets of lattice coefficients which are robust to quantization. Two complementary methods are presented which are key elements to derive low dynamic range solutions while satisfying given frequency specifications. The first possible technique is based on a rearrangement of the elementary blocks involved in the cascade structure, and the second is a sequential design method which, for given weighting factors related to the frequency specifications, leads to a minimal dynamic range of the lattice coefficients. Two design examples, illustrating each of these techniques, show quantisation results with a reduced number of bits which yield frequency results close to infinite precision solutions.