Roving Emulation asa FaultDetection Mechanism

In this paperwepresent anewbuilt-in test method- ologyfordetecting andlocating faults indigital systems. The technique iscalled roving emulation andconsists ofanoff-line snapshottypeemulation orsimulation ofoperating components inasystem. Itsprimary application isintesting systems inthe field wherereal-time fault detection isnotrequired. Theprimary performance measureofthistestschemaistakentobethe expected value oftheerrorlatency, i.e., thetimerequired to detect afault onceitfirst occurs. Theprimary results ofthis paperdealwithderiving equations fortheerrorlatency. We present bothaprobabilistic andservice-waiting modeltoanalyze theexpected error latency inasystem tested viaroving emulation. Theeffects ofvarious controllable anduncontrollable system parameters onerror latency arestudied. Finally, thetechnique is applied toasystem consisting ofcombinational logic modules, andnumerical results arepresented.