Self-checking comparison circuits (comparator)

The paper deals with the construction of self-testing and fault-tolerant computing systems and, in particular, with self-checking comparison circuit (comparator) for output signals of several blocks of computing system. Two-output and one-output self-checking comparators are considered. The conditions for self-testability of proposed comparison circuit are formulated. It appears that one-output comparator is completely self-testable relative to all multiple constant faults for all elements of the system. Constructed comparator has several merits in comparison with known ones. In particular, the comparator ensures fixed delay of the signals independently of the number of comparing outputs and detection of all multiple faults. The example is considered.