A self-optimizing digital data transmission set

A transmission set which responds to changing link conditions with automatic accommodations in bit rate and coding is described. The basic capability of the system is a simultaneous twin decision on each incoming bit: (1) a binary decision as to whether the bit is “1” or “0” and (2) an auxiliary binary decision as to whether the bit is equivocated (gray) or not gray. The analytical relationships between bit grayness and bit error and also bit grayness and bit rate are explored. On the basis of these relationships, the quantitative criteria for speed and code changing requests are developed. The ability of the set dynamically to accommodate the basic information rate to a prescribed security level in the face of changing link conditions is then shown.