ADAPTIVE IIR COMB FILTER FOR HARMONIC SIGNAL CANCELLATION

A novel adaptive infinite impulse response (IIR) comb filter structure for the estimation and elimination of harmonic interference signals i s presented. Two filter blocks are presented. The first is an adaptive notch filter implemented by a computationally simple but exact gradie nt-based algorithm. The adaptive notch filter is used to estimate and track the fundamental frequency of the harmonic series. The second blo ck is a tunable IIR comb filter whose parameters are determined based on the estimate of the fundamental frequency. The purpose of both filt er blocks is to effectively cancel the harmonic series. The proposed c omb filtering is more robust as well as computationally simpler than t he comb filtering technique used by Nehorai and Poraz (1986). Error su rface analysis is included to indicate that the error surface characte ristics for the proposed solution is a significant improvement when co mpared to the conventional adaptive comb filter approach used by Nebor ai and Poraz (1986). Simulation results are included to demonstrate th e performance characteristics of the proposed solution.