Step Response Time Error of RC Distributed Line by Approximating Discrete Elements

Abstract

This paper analyses quantitatively approximation error of RC distributed line by discrete elements. It is to be clarified that with a normal RC ladder approximation, error evaluated in the response time becomes as large as a few per cents even when a RC distributed line is replaced with as many as 50 small discrete RC elements. In the paper, more efficient approximation, which makes the error small enough to be neglected using some ten discrete elements only, is to be introduced. The proposed approximation is applied to the unit step response analysis of the potential divider for the switching impulse voltage and its effectiveness is confirmed in comparison to the measured waveform.