Feedback in Synchronous Sequential Switching Circuits

In this paper we consider minimum feedback loop realizations of synchronous sequential switching circuits. It is shown that any finite state sequential function can be realized as a synchronous sequential circuit with a single feedback loop, or equivalently, as a one-dimensional iterative circuit with one amplifier between stages. Techniques are described which enable us to find such a realization for a given flow table. A simple test procedure is described to determine if a sequential function can be realized as a sequential circuit using its output function as feedback, whether the output is completely or incompletely specified.