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.