THE DISTINGUISHING FUNCTIONS IN TEST GENERATION OF DIGITAL SEQUENTIAL CIRCUITS WITH MULTIPLE OBSERVATION TIME STRATEGY

Abstract

An analytical approach is considered to test generation for circuits with memory which is based on method of the distinguishing functions. It uses the symbolic simulation and multiple observation time strategy of output signals, which can improve the fault coverage of test. We consider two forms of distinguishing function – disjunctive and conjunctive. Disjunctive form identifies distinguishable state pairs of good and faulty circuits and reduces the problem of test generation to verifying tautologies of distinguishing function. Conjunctive form determines the pairs of indistinguishable states and reduces the problem of test generation to satisfiability of Boolean functions problem (SAT).