A Genetic Algorithm for the Design of Tunable Fractional-Delay Allpass IIR Filter Structures

A genetic algorithm (GA) based optimization approach for the design of tunable fractional-delay (FD) digital filters is presented. In the proposed approach, the FD filter is designed by using the allpass IIR based Farrow structure (FS). The approach exploits the advantages of a global search technique to determine the coefficients of the allpass IIR FS. It involves a binary encoding scheme for chromosome construction and the optimization is carried out by minimizing an objective function based on the phase delay error. Experimental results show that the GA based approach leads to an improved delay characteristic relative to that achieved by using a least-squares approach.