NULLATOR NORATOR APPROACH TO ANALOG CIRCUIT DIAGNOSIS USING GENERAL-PURPOSE ANALYSIS PROGRAMS

In this paper a decomposition approach to diagnosis and fault prediction in large analogue and switched capacitor circuits is proposed, reduced to an analysis of the corresponding nullator-norator models at a single test frequency. Algorithms for isolation of faulty nodes and subcircuits are presented. The topological conditions for performing diagnosis of faulty nodes and for identification of faulty elements have been considered. The element tolerance variations and measurement errors have been taken into account. The possibilities of the general-purpose programmes for frequency and worst-case analysis have been used in the practical implementation of diagnosis and fault prediction. Diagnosis of benchmark circuits has been performed and the results of a computer simulation using the programme PSpice are presented.