Equiripple Design of QMF Banks Using Digital Allpass Networks

Xi ZHANG  Hiroshi IWAKURA  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E78-A   No.8   pp.1010-1016
Publication Date: 1995/08/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: Digital Signal Processing
Keyword: 
digital filter,  allpass network,  QMF bank,  design method,  

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Summary: 
In this paper, we discuss design of quadrature mirror filter (QMF) banks using digital allpass networks in the frequency domain. In the QMF banks composed of a parallel connection of two allpass networks, both aliasing error and amplitude distortion are always completely canceled. Therefore, we only need to design the analysis filters and eliminate phase distortion of the overall transfer function. We consider design of the QMF banks in two cases where phase responses of the filters are repuired or not required. In the case where the phase responses are not required, the design problem can be reduced to design of phase difference of two allpass networks. In the case where the phase responses are required, we present a procedure for designing the QMF banks with both equiripple magnitude and phase responses.