An UltraPrecise Time Synchronization System Designed by

Any two independent time scales wil l exhibit time departure due to two main causes, i.e., systematic differences in the frequency standards and in-herent random noise processes. For time synchronization, theoretical consider-ations indicate that a third-order feedback systsm wil l automatically remove the systematic difficulties of typ ica l frequency standards used in time scale work. The whole system i s simulated with a computer to determine the systems feasibiliff rnd operating parameters. I n this treatment we assume that time comparisons for synchronization would be intermittent and that the frequency standard may be represented by a systematic linear frequency drift with a random flicker noise spectrum ( l / ( f l) of the frequency fluctua-tions. On the basis of the computer results an electromechanical system was designed and built. When the input to the system is the frequency from a high quality quartz crystal oscillator, the output frequency has no measur-able frequency drift. I f synchronization is performed every 12 hours, the rms time error predictad by the system for the time of the next synehronira-tion i s 70 nanoseconds, which is near theoretical optimum