Simple analogue active filter testing using digital modelling

Abstract

This paper presents a new approach to detect analogue catastrophic faults via digital modelling for an analogue filter. Area of interest in this paper is to prove that analogue circuit can be translated into logic gates (0's or 1's) and investigates the effectiveness of analogue fault (short and open) in analogy approximate to digital stuck-at fault model. The purpose of testing fault that connects active component to supply terminal (stuck-at fault) is to investigate the characteristic of the output response, whether can successful model analogue fault to logic level. The approach is to sensitise primary input with an arbitrary frequency square-wave as stimuli and observes output signature in transient and frequency response in order to distinguish Go or No-GO. It is a simple method to accelerate production test without any extra circuitry. This approach has been implemented to a frequency-dependant circuit (Butterworth low pass filter) in order to verify its functionability.