Soft Fault Diagnosis of Analog Circuits via Frequency Response Function Measurements

This paper provides a novel method for single and multiple soft fault diagnosis of analog circuits. The method is able to locate the faulty elements and evaluate their parameters. It employs the information contained in the frequency response function (FRF) measurements and focuses on finding models of the circuit under test (CUT) as exact as possible. Consequently, the method is capable of getting different sets of the parameters which are consistent with the diagnostic test, rather than only one specific set. To fulfil this purpose, the local plolynomial approach is applied and the associated normalized FRF is developed.The proposed method is especially suitable at the pre-production stage, where corrections of the technological design are important and the diagnostic time is not crucial. Two experimental examples are presented to clarify the proposed method and prove its efficiency.