摘要：本文介绍了网络时间协议的基本工作原理,简要分析了在网络路径对称和不对称两种情况下的网络时延问题。论述了网络时间服务器的构建方法和网络授时软件的设计流程。应用数据统计,对网络时延和时差作了详细分析,给出了在软件设计中处理与网络时延和时差相关问题的方法。最后阐明了建立网络时间服务体系的必要性。

摘要：基于双混频时差技术设计研制了8通道的频率稳定度测量系统,实现了对8路5 MHz或10 MHz频率标准的测量.当频率为10 MHz取样时间为1 s时,系统噪声本底优于2.0 X 10^(-13),取样时间为1000 s时,系统噪声本底优于2.5×10^(-16).不但可以满足原子时标基准原子钟组的内部比对,也可实现对一般频率标准的检定和校准.Abstract：Based on the technique of Dual Mixer Time Difference (DMTD), an 8-channel frequency stabilitymeasurement system has been developed. It realized the measurement of 8-channel 5 MHz and 10 MHz frequencystandards. For 10 MHz frequency, the noise floor is better than 2.0 ×10^(-13)/1 s, 2.5× 10^(-16)/1000 s. It can not only satisfy the internal comparison of time scale ensemble, but also can realize the calibration of normal frequency standards.