摘要
Time comparison experiment via laser pulses has been made between the two sections of the Shanghai Observatory, Xujiahui and Sheshan, separated by 25.2km. In the experiment, a Q-switch ruby laser, photo-receiving systems, 0.1 nsec resolution counters as well as rubidium clocks were used. Time fluctuations of about ±1.3 nsec (r.m.s.) for two-minute measurements were obtained.
