Analysis of the Signal Reliability Measure and an Evaluation Procedure

The classical reliability measure of digital circuits, known as functional reliability, assumes that the circuit fails whenever a fault is present in it. It has long been known that this reliability measure is overly pessimistic since digital circuits may produce correct output signals even when some faults are present in them. A different reliability measure, known as signal reliability, is the probability that the circuit output is correct. This reliability measure is analyzed first and compared to the functional reliability measure. Next, a new procedure for the evaluation of the signal reliability measure is presented.