The Equiripple Approximation Method for Designing All-pass Digital Filters
Weiqing Liu · Xihua Daxue xuebao. Zhexue shehui kexue ban · 2013
A method for designing digital all-pass filter using the equiripple approximation of Chebyshev is presented.The denominator polynomial of a stable all-pass filter is certain to have a minimum-phase.Based on the relationship between the delay function and the cepstral coefficients,the complex cepstral coefficients can be determined by the best uniform approximation criterion;by the complex cepstral coefficients,the all-pass filter denomination coefficients are obtained based on the relation between the complex cepstrum coefficient and the stable minimum phase sequence.The all-pass transfer function is completely determined from its denominator coefficients.The group delay of designed filter can approximate the desired group delay in all band,and the error distributes uniformly.