Simultaneous Approximation for Magnitude and Phase Responses of FIR Digital Filters

Masahiro OKUDA  Masahiro YOSHIDA  Masaaki IKEHARA  Shin-ichi TAKAHASHI  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E87-A   No.11   pp.2957-2963
Publication Date: 2004/11/01
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: Digital Signal Processing
FIR filters,  complex Chebyshev approximation,  least squares method,  

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In this paper, we present a new numerical method for the complex approximation of FIR digital filters. Our objective is to design FIR filters with equiripple magnitude and phase errors. The proposed method solves the least squares (LS) problem iteratively. At each iteration, the desired response is updated so as to have an equiripple error. The proposed methods do not require any time-consuming optimization procedure such as the quasi-Newton methods and converge to equiripple solutions quickly. We show some examples to illustrate the advantages of our proposed methods.