Design for Stable IIR Perfect Reconstruction Filter Banks Using Allpass Filters

This paper presents a new method for designing two-channel IIR linear phase filter banks that satisfy both the perfect reconstruction and stability conditions, using allpass filters. Using the perfect reconstruction condition for filter banks, we first offer a class of structurally perfect reconstruction implementations. Since the proposed filter banks must satisfy the perfect reconstruction condition even though the filter coefficients are quantized, the design problem becomes the design of half-band filters using a delay section and an allpass filter. Therefore, stable IIR perfect reconstruction filter banks can be easily obtained by approximating the phase responses of just the allpass filters. From the viewpoint of wavelets, a new method is presented for designing half-band filters with arbitrary flatness based on the parallel connection between the delay section and the allpass filter. Furthermore, by using two different allpass filters in the filter banks, the magnitude responses of lowand high-pass filters can be designed arbitrarily. © 1998 Scripta Technica, Electron Comm Jpn Pt 2, 81(5): 24–32, 1998