Equivalent Sequential Circuits

Three types of sequential circuits are defined, two of which are synchronous and one of which is asynchronous. The concept of equivalent sequential circuits as discussed by Huffman, Mealy, and Moore is extended to circuits of different types. Transformation procedures are given for transforming a state table of one type into state tables of the other types. One of these transformations can also be used to introduce unit delay between corresponding inputs and outputs for a synchronous circuit. The transformation methods allow a comparison of circuits, or state tables of different types to be made for a given sequential circuit problem. A few general conclusions are drawn about the different types of sequential circuits.