The paper describes a novel development of the Viterbi algorithm detector that is suitable for the detection of a convolutionally coded digital signal. The technique enables a substantial reduction in equipment complexity to be achieved, relative to that of the Viterbi algorithm detector, with only a very small reduction in tolerance to noise. Results of computer-simulation tests are presented showing the performance of the system and giving also a measure of its complexity, for the particular case of a coded 8-level PSK signal. An outline is also presented of a possible implementation of the new detector for the given application.