VLBI测站时频自动切换系统的设计和实现

Design and Implementation of a Time Frequency System with Auto-Switching Clocks at a VLBI Station

时频系统作为VLBI测站的主要设备之一,为测站提供稳定可靠的频率时间标准,其信号的好坏直接影响数据处理质量。时频系统的关键设备是氢原子钟,在工程应用中测站配备两台以上的氢原子钟以确保任务完成,但是由于有多路信号需要切换,且长时间切换会造成信号的中断,需要更换数据处理模型,严重的会引起数小时的数据丢失,因此如何做到快速高效地切换是值得研究的课题。提供一种经济有效的自动切换方法的研究和实现方式。

As a major equipment of a VLBI station, an effective time frequency system supplies stable and reliable time/frequency data for the station.The signals from such a system will directly affect the quality of data processing.The key device in a time frequency system is its hydrogen clock.In order to ensure accomplishing observational tasks, a VLBI station is engineered to be equipped with at least two hydrogen clocks.Using multiple hydrogen clocks requires switching between different routes of signals.A long duration conventionally needed for switching will cause interruption of signals, and make it necessary to replace the data-processing model after a switch.In the worst cases signal interruption can result in loss of data in several hours.It is rather worth to study fast and efficient approaches to switch hydrogen clocks.In this paper we present a design of a cost-effective time frequency system with auto-switching hydrogen clocks.We also describe our implementation of the system and its practical effectiveness.