Error detection carried out by the use of unused modulo-m code

Abstract From the Canadian patent

In an error detection circuit for use in detecting an error in a binary signal of k bits in a logic circuit which carries out a predetermined operation with respect to a modulus number m where m is, equal to 2k-1, zeroth through (m-1)-th codes are assigned to the predetermined operation while an m-th code is prepared as a specific code to monitor and to detect an error in the error detection circuit. The logic circuit may be either one of a modulo-m register circuit, a modulo-m coincidence circuit and a modulo-m, calculation circuit. Alternatively at least two of the, modulo-m circuits may be combined to form the logic circuit. If m = 3, the specific code may be (1 1).