DocumentCode :
1022189
Title :
Two-channel IIR QMF banks with approximately linear-phase analysis and synthesis filters
Author :
Ekanayake, Mahes M. ; Premaratne, Kamal
Author_Institution :
Dept. of Electr. & Comput. Eng., Miami Univ., Coral Gables, FL, USA
Volume :
43
Issue :
10
fYear :
1995
fDate :
10/1/1995 12:00:00 AM
Firstpage :
2313
Lastpage :
2322
Abstract :
Perfect linear-phase two-channel QMF banks require the use of finite impulse response (FIR) analysis and synthesis filters. Although they are less expensive and yield superior stopband characteristics, perfect linear phase cannot be achieved with stable infinite impulse response (IIR) filters. Thus, IIR designs usually incorporate a postprocessing equalizer that is optimized to reduce the phase distortion of the entire filter bank. However, the analysis and synthesis filters of such an IIR filter bank are not linear phase. In this paper, a computationally simple method to obtain IIR analysis and synthesis filters that possess negligible phase distortion is presented. The method is based on first applying the balanced reduction procedure to obtain nearly allpass IIR polyphase components and then approximating these with perfect allpass IIR polyphase components. The resulting IIR designs already have only negligible phase distortion. However, if required, further improvement may be achieved through optimization of the filter parameters. For this purpose, a suitable objective function is presented. Bounds for the magnitude and phase errors of the designs are also derived. Design examples indicate that the derived IIR filter banks are more efficient in terms of computational complexity than the FIR prototypes and perfect reconstruction FIR filter banks. Although the PR FIR filter banks when implemented with the one-multiplier lattice structure and IIR filter banks are comparable in terms of computational complexity, the former is very sensitive to coefficient quantization effects
Keywords :
IIR filters; all-pass filters; approximation theory; band-pass filters; delay circuits; filtering theory; quadrature mirror filters; FIR prototypes; IIR filter bank; allpass IIR polyphase components; approximately linear-phase analysis filters; approximately linear-phase synthesis filters; balanced reduction procedure; coefficient quantization effects; computational complexity; filter parameters optimisation; finite impulse response filters; infinite impulse response filters; magnitude error bound; objective function; perfect reconstruction FIR filter banks; phase distortion; phase error bound; postprocessing equalizer; stopband characteristics; two-channel IIR QMF banks; Computational complexity; Design optimization; Equalizers; Filter bank; Finite impulse response filter; IIR filters; Linear approximation; Nonlinear filters; Phase distortion; Prototypes;
fLanguage :
English
Journal_Title :
Signal Processing, IEEE Transactions on
Publisher :
ieee
ISSN :
1053-587X
Type :
jour
DOI :
10.1109/78.469858
Filename :
469858
Link To Document :
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