Efficient design of FIR filter based low-pass differentiators for biomedical signal processing

Abstract

This paper describes an alternative design of linear phase low-pass differentiators with a finite impulse response (type III FIR filter). To reduce the number of necessary filter coefficients, the differentiator's transfer function is approximated by a Fourier series of a triangle function. Thereby the filter's transition steepness towards the stopband is intentionally reduced. It can be shown that the proposed design of low-pass differentiators yields to similar results as other published design recommendations, while the filter order can be significantly reduced.