On the recovery of error patterns from signatures obtained in digital system testing

Error patterns are lost in the data compression process inherent in signature analysis. These however contain useful information about the faults in faulty units. The present paper investigates the possibility to recover the lost error patterns from the signatures obtained at the end of a test run. It is shown that, the recovery is possible if the test outcome sequence is not longer than the signature analyser period and if the number of possible error signatures can be reduced to a subset a priori known.