A novel approach to design optimal digital FIR filter based on logistic distribution based approximation

Abstract

ABSTRACT This work proposes a novel methodology to design FIR lowpass filter (LPF) using logistic probability distribution function. Desired magnitude response of the FIR filter is approximated as sum of equi-spaced logical function waveforms with their mean varying at definite interval. The required number of logistic waveforms and its standard deviation depends on the parameters of designed filter specifications. Simulation results have been compared with optimal Method (Park McClellan) and windowing technique to show the superiority of the proposed method. It is found that ripples in pass band and stop band of the filter has been reduced iteratively, higher stop band attenuation is achieved. The proposed method also provides a close design way to link coefficients of the filter to design specification directly.