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Unformatted text preview: Logic and Fault Simulation 153 are critical nets; however, L and E are not critical because changing their values does not affect the circuit output. The critical path tracing is stopped due to the reconvergence of fanout branches L and F . Eventually, faults F/ 1, J/ 0, K/ 1 are detected. One solution to this fanout reconvergence is to partition the circuit into fanout-free subcircuits. The detailed implementation of the critical path tracing can be found in [Abramovici 1984]. A modified critical path tracing technique that is linear time, exact, and complete can be found in [Wu 2005]. 126.96.36.199 Statistical Fault Analysis Instead of performing actual fault simulation, the statistical fault analysis (STAFAN) approach proposes to use probability theory to estimate the expected value of fault coverage [Jain 1985]. The detectability of fault f ( d f ) is the probability that fault f is detected by a random pattern. STAFAN calculates the detectability of a fault by two numbers: controllability and observability. Theof a fault by two numbers: controllability and observability....
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- Spring '08