Abstract: A system and process for receiving phase-coherent FSK signals having data and clock components which includes a plurality of subsystems and a means for carrying data among the subsystems. At least two of the subsystems are able to communicate by means of a transmitter in one of them and a receiver in the other. The receiver includes a demodulator for separating the data and clock components of the encoded phase-coherent FSK signals. The clock demodulator includes a first transition detector and a 90-degree phase shift circuit which both receive the encoded signal. A second transition detector receives the output of the phase shift or phase delay circuit. An OR gate receives the output of the first and second transition detectors to produce a four times clock signal. The data component of the phase-coherent FSK signal is recovered by either of two alternate circuits.