THE DESIGN OF 2-CHANNEL PERFECT RECONSTRUCTION IIR FILTER BANKS WITH CAUSALITY

A necessary condition for filter banks is the perfect recovery of inpu t signal from the output signal which may be called tile perfect recon struction condition. Moreover, for real-time processing, design of cau sal system is also an essential element. In the conventional allpass f ilter, it is difficult to satisfy the perfect reconstruction condition and causality at the same time. In this paper, a two-channel IIR filt er is designed which solves these problems, Using the polyphase struct ure, the perfect reconstruction condition is newly presented. Lagrange -multiplier and Lagrange-Newton methods, used for optimization and des ign method based on this condition, are described. Moreover, the valid ity of this method is shown by computer simulations. (C) 1998 Scripta Technica.