Sequence reordering to improve the levels of compaction achievable by static compaction procedures

We describe a reordering procedure that changes the order of test vectors in a test sequence for a synchronous sequential circuit without reducing the fault coverage. We use this procedure to investigate the effects of reordering on the ability to compact the test sequence. Reordering is shown to have two effects on compaction. (1) The reordering process itself allows us to reduce the test sequence length. (2) Reordering can improve the effectiveness of an existing static compaction procedure. Reordering also provides an insight into the detection by test generation procedures of faults that are detected by relatively long subsequences