THE SIMULTANEOUS APPROXIMATION OF MAGNITUDE AND PHASE BY FIR DIGITAL FILTERS. II: METHODS AND EXAMPLES

In the present second part of this paper the relations between earlier approaches, the new approach in part I of the paper and the problem of simultaneous approximation of magnitude and phase are discussed. In particular, we begin by reconsidering the methods of Cuthbert and Holt et al., Steiglitz, and Chen and Parks which are predecessors of our method. Afterwards, results of numerical experiments are presented. We especially design filters considered previously by other authors and compare the results obtained by our approach with others. These filters are obtained by the solution of unconstrained approximation problems. We finally demonstrate the abilities of our approach by presenting two filters, especially one of length 1000, where the requirements lead to additional constraints in the design problem. © 1997 by John Wiley & Sons, Ltd.