COMPOSITION METHOD TO REALIZE SELF-CHECKING FAULT LOCATORS.

A fault locator is a self-checking functional unit which identifies a faulty module in a self-checking system constructed with self-checking modules (subsystems) by collecting and observing the test outputs from each module. Faulty modules are identified by observing the syndrome corresponding to the preset input code space and identifying to which module fault the input coding subspace corresponds. Since the inputs to the fault locator are given as vectors of the preset coding subspace in this case, there may not be a sufficient number of vectors to self-test the fault locator. Thus we present a method to construct a self-checking fault locator by using permuters for inputs to provide sufficient input vectors for self-testing.