Test vector chains for increased resolution and reduced storage of diagnostic tests

The use of diagnostic test sets improves the accuracy of defect diagnosis by allowing smaller sets of candidate defect sites to be obtained. However, diagnostic test sets are significantly larger than fault detection test sets, and the complexity of deterministic diagnostic test generation is higher because of the need to consider pairs of faults. This work studies a solution that addresses both the size of a diagnostic test set and the complexity of deterministic diagnostic test generation through the use of what are called test vector chains. Test vector chains provide a specific algorithm for obtaining new tests from existing ones through single-bit changes. They allow smaller test sets to be stored, and additional tests to be obtained by computing test vector chains or subsets thereof. Experimental results demonstrate that tests obtained through test vector chains are effective as diagnostic tests, and that the resulting storage requirements are close to those of fault detection test sets.