Multiple Fault Diagnosis in Combinational Networks

The concept of prime faults is introduced for the study of multiple fault diagnosis in combinational logic networks. It is shown that every multiple fault in a network can be represented by a structurally equivalent fault with prime faults as its only components. Functional and structural masking and covering relations among faults are defined. These relations can be exploited to greatly simplify multiple fault analysis and their test generation. We present an efficient algorithm that generates a multiple fault detection test set and identifies redundancies. Suggestions for designing networks to yield a minimum number of tests in the multiple fault detection test set are also included.