A New Approach to Stability Evaluation of Digital Filters

Abstract

In this paper, a new numerical method of evaluating digital filter stability is presented. This approach is based on novel root-finding algorithms at the complex plane using the Delaunay triangulation and Cauchy's Argument Principle. The presented algorithm locates unstable zeros of the characteristic equation with their multiplicities. The proposed method is generic and can be applied to a vast range of systems. Verification of this method is presented with benchmarks that include integer-order and fractional-order digital filters.