Synchronous Sequential Machines: A Modular and Testable Design

It will be shown that a single-input n-definite machine realized by a universal modular tree, in which each module consists of AND-EXCLUSIVE-OR-DELAY (AND-EOR-DELAY) as a basic element, can be tested for single stuck-type-faults by tests of length 2n + 3 only. This is a marked improvement over the previous results for trees consisting of AND-OR-DELAYS, which are known to have test lengths of exponential growth.