Allpass lattice structure based second order digital IIR notch filter for removing DC and very low frequencies

In this paper, an allpass lattice structure based second order notch filter with notch at DC is designed. The filter perfectly removes the dc and the specified very low frequencies. It can be designed for a very sharp transition band thereby eliminating frequencies close to DC. The filter is simple to implement and the number of multipliers required is equal to one. For the purpose of illustration, the filter is designed to meet a cutoff frequency of 1 Hz for a sampling frequency 800 Hz and applied to remove the baseline wander in ECG signals.