A special aspect of sequential machine identification is treated in this paper. Given an input signal sequence to an unknown sequential machine and the resulting output signal sequence of the machine, it is necessary to find a state table or any other description of the machine and all other machines which response to the given input sequence with the given output sequence. The main objective of the research was to develop a fast and efficient state merging method which profits from the special characteristics of the problem at hand.

This paper describes a new method for the state minimization of incompletely specified sequential machines. Previously described methods start with generating all maximal compatibles of states of the original incompletely specified machine and then try to find a closed cover which consists of a minimal number of MCs or portions of MCs. This process involves a long enumeration process and, as the number of states grows, turns out to be impractical for hand calculation.

The numerical integration performed in a digital differential analyzer (DDA) is always associated with a truncation error [1,2]. This correspondence deals with truncation errors generated when the direction of the independent variable (the sign of the △X) is reversed, which will be subsequently referred to as reversibility errors.