一、概述 ZJ型自校数字钟(简称自校钟)是为提高地震观测台站时间服务质量而研制的新型计时仪器。它有较高的计时精度,对于BPMC标准时间的最大钟差不大干25毫秒。用于台站地震观测记录,可以比以前更准确地计算地震参数。对于一般的地震分析研究工作,这样小的钟差可以忽略,即作零钟差处理。自校钟具有准确、可靠的自动校时功能,校时后,对于BPMC标准时间的钟差不大于3毫秒。显然,自动校时比目前一般台站采用的人工校时更准 First, an overview ZJ-type self-school digital clock (self-school bell) is to improve the time service quality of seismic observation station and developed a new type of timing instruments. It has a high timing accuracy, with a maximum clock delay of 25 ms for BPMC standard time. For station seismic observations, seismic parameters can be calculated more accurately than before. For the general seismic analysis work, such a small clock error can be ignored, that is, for zero-clock processing. Since the school bell with accurate, reliable automatic timing function, after school, for BPMC standard time clock difference of not more than 3 milliseconds. Obviously, the automatic calibration is more accurate than the manual calibration currently used in general stations