METHOD FOR PROPAGATING UNKNOWN DIGITAL VALUES IN A HARDWARE BASED COMPLEX CIRCUIT SIMULATION SYSTEM

摘要

ABSTRACT OF THE DISCLOSUREIn a circuit system simulation model whichmay comprise a combination of the physical device to bemodeled and means for controlling the physical deviceat normal operating speeds, a method is provided forpropagating a simulated unknown signal value whichcomprises exciting the simulation model with differingpattern sequences a plurality of times, during eachexcitation sequence changing at least one input valuein the input sequence, comparing the sampled values ofeach resultant output signal, and setting orrecognizing as an unknown value any specific outputsignal which differs as a result of the change in theinput sequence. Modification, repetition, sampling andcomparison of patterns may be repeated a number oftimes. Only a fraction of the possible input patternsneed to be presented to indicate the propagation ofunknown values.