Low-sensitivity recursive digital filters obtained via the delay replacement

A method is proposed for synthesizing very low-sensitivity recursive digital filters on the basis of three techniques: 1) delay replacement; 2) transformation of resistance-terminated reactive ladders into digital structures; 3) multiplier scaling. The method applies to the case where the poles of the transfer function of the filter are near z = 1 , as is the case when the sampling rate is increased. The low-sensitivity property of the resulting schemes is proved and illustrated by examples.