Realization of Fault-Tolerant and Fail-Safe Sequential Machines

Given a synchronous sequential machine M, this correspondence deals with the fault-tolerant realization M of M and also its fail-safe realization M on the assumption that the faults that can occur to the circuitry of M or M are of permanent stuck-at type and the total number of faults can be at most some preset positive integer r. First, the realization of M or M is derived for r = 1 and then the same idea is extended to have the realization for any arbitrary r. It has been shown that the realization of M is such that it is also able to tolerate faults of nonpermanent nature.