基于晶振的远程时间同步参考源性能分析

Performance analysis of remote time synchronized reference source based on crystal oscillator

针对用户需求结合资源条件,中国科学院国家授时中心实现了主站以高稳晶振作为参考时钟,在直线距离约300 km的从站复现出与参考同步的时频信号,使相距数百千米的两个站点之间保持时频同步。根据应用场景特点,设计了针对高稳晶振的性能测试方案,通过试验分析,发现高稳晶振的准确度对两地时间同步精度影响较大。为保证在不具备外部驯服条件下的主从站间的同步性能,通过对主站高稳晶振进行机械调准,使两站点间时差峰峰值从190 ns降低到60 ns,标准差(STD)达到了15 ns以内,满足了两站点间时间同步应用需求。通过分析测试结果,若需进一步提高两地同步精度,可以从改善参考源的频率稳定度和频率准确度两方面入手。

According to the user’s demand and resource conditions,the NTSC(the National Time Service Center,Chinese academy of sciences)has reproduced the time-frequency signal synchronizing with the reference clock in the slave station with a straight-line distance of 300 km based on the high stability crystal oscillator in the master station,and realized the time-frequency synchronization between two stations hundreds of kilometers apart.According to the characteristics of the application scenario,a performance test scheme for high stability crystal oscillator is designed.It is found that the frequency accuracy of high stability crystal oscillator has a great influence on the time synchronization accuracy.To ensure the synchronization performance between master and slave sites in the absence of external taming conditions,the high stability crystal oscillator of the master station is mechanically adjusted.After the adjustment,the peak value of the time difference between the two stations is reduced from 190 ns to 60 ns,and the standard deviation(STD)is within15 ns,which met the application requirements of time synchronization between two stations.According to the analysis of test results,further improvement of the synchronization accuracy can be obtained by improving the frequency stability and frequency accuracy of the reference source.