A comb filter design using fractional-sample delay

In this paper, a new comb filter design method using fractional sample delay is presented. First, the specification of the comb filter design is transformed into that of fractional delay filter design. Then, conventional finite impulse response (FIR) and allpass filter design techniques are directly applied to design fractional delay filter with transformed specification. Next, we develop a constrained fractional delay filter design approach to improve the performance of the direct design method. Finally, several design examples and an experiment of the power line interference removal in electrocadiogram (ECG) signal are demonstrated to illustrate the effectiveness of this new design approach. Index Terms - Comb filter, fractional delay filter, harmonic interference removal.