Note on Finite-Memory Sequential Machines

One of the design problems of digital computers is in code conversion from analog form to its equivalent digital form, and vice versa. In data logging, reduction, and process control applications of digital computers, input data are frequently in analog or shaft position form. Conventionally weighted binary numbers are not used directly for analog readings because at certain positions these may be ambiguously expressed. Gray suggested a code in this application which eliminates the ambiguity of natural binary numbers. The basic rule in Gray code generation is to allow only one bit change between adjacent numbers.1 The Gray code, unfortunately, is difficult to use in computation. Hence, it is customary to perform code conversion before attempting computer arithmetic operations.