Note on Feedforward Inverses for Linear Sequential Circuits

A necessary and sufficient condition for the existence of a feedforward inverse for a linear sequential circuit is presented. As a result of the proof of this existence condition, a procedure for construction of feedforward inverses, when they exist, is developed. It is shown that the delay of the inverse that is realized by the construction procedure is minimal over all inverse circuits. This work is a generalization and extension of certain results obtained by Massey and Sain concerning the existence of feedforward inverses of feedforward linear sequential circuits.