Adaptive notch filtering in impulsive noise environment

An adaptive digital notch filter is considered for 50/60 Hz line frequency signal processing. An adaptive algorithm allows tracking of the main frequency component such that the notch frequency is the only changing parameter. Since the power line frequency is known to within a narrow tolerance band, it is possible to apply soft or hard limiting on the notch frequency. Soft and hard limiting are compared for Laplacian noise, and the effect of filtering is investigated for a signal with strong harmonic contents.