A novel IIR filter delay equalizer design approach using a personal computer

A discrete-time approach to solving the group delay approximation problem is presented using digital all-pass functions for equalizing a digital recursive filter or communications channel. An algorithm for personal computers, called Two Stage, for finding the digital all-pass transfer function that meets a given requirement on delay error is presented. Typically, the percentage of error achieved can be less than 1% if needed and is a function of the number of all-pass sections used for a given bandwidth-the more all-pass sections, the smaller the error