A new adaptive analog test and diagnosis system

This paper presents a low-cost analog test system with diagnosis capabiliti es. The tester is able to detect faults in any linear circuit by learning a reference circuit behavior in a first step, and comparing this behavior ag ainst the output of the circuit under test in a second step. For a faulty c ircuit, a third step takes plate to locate the fault, The diagnosis method consists on injecting probable faults in a mathematical model of the circui t, and later comparing its output with the output of the real faulty circui t. This system has been successfully applied to a case study, a biquad filt er. Soft, large, and hard deviations on components, as well as faults in op erational amplifiers, were considered. Experimental results have proven the feasibility and efficiency of the proposed test and diagnosis system.