Type-4 2-D Diagonal and Four-Fold Rotational Symmetry Digital Filter Architectures

Abstract

In this paper, Type-4 two-dimensional (2-D) separable denominator IIR filter architecture is studied. This structure has a critical path of one multiplication and three additions. Using this Type-4 2-D separable denominator IIR filter architecture, three new 2-D IIR filter structures with diagonal and four-fold rotational symmetries are given. These structures have a critical path of one multiplication and four additions. Further, using a different coefficient constraint, a new Type-3 2-D diagonal symmetry IIR filter architecture with a critical path of one multiplication and two additions is obtained. In all, four different 2-D IIR filter architectures with diagonal and four-fold rotational symmetries are presented.