Application of asymmetrical periodic signals as test vectors for analog fault detection: a novel perspective of classical concepts

Authors: BADAR UD DIN AHMED, WANG YOUREN, NAJAM-UD-DIN AHMED

Abstract: Analog fault diagnosis is a field of paramount importance, and test signal generation is an important prerequisite for analog fault detection. Several stimuli have been used as input test vectors. This study presents a novel approach for the adoption of classical methods and signals for fault detection. This involves the use of asymmetrical periodic signals and comparison of their effectivity in maximizing output response between faulty and conforming circuits. The technique helps to determine a minimal set of test signals for a circuit. It also enables the test designer to identify the parts of the frequency spectra of various signal types that can pose problems of fault masking and fault dominance. In addition, the technique indicates certain sets of components forming ambiguity groups, which exhibit complementary fault-masking effects. The method does not require access to internal nodes of the circuit. It only requires generation of standard asymmetrical signals and hence can be implemented with the use of commonly available function generators. The technique is applicable to integrated circuits and printed circuit boards, as well as analog subsystems. It can also be applied for fault isolation. The results include responses from representative benchmark analog circuits.

Keywords: Analog fault detection, analog test vector generation, asymmetrical periodic signals

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