喷泉钟驾驭恒温晶振方法研究  

Research on the steering OCXO by the fountain clock

作　　者：肖娅聪 刘昆[1] 刘洪康 房芳[1] 陈伟亮[1] 戴少阳 郑发松 李天初[1] XIAO Yacong;LIU Kun;LIU Hong-kang;FANG Fang;CHEN Wei-liang;DAI Shao-yang;ZHENG Fa-song;LI Tian-chu(National Institute of Metrology,Beijing 100029,China;Beijing Institute of Technology,Beijing 100081,China)

机构地区：[1]中国计量科学研究院,北京100029 [2]北京理工大学,北京100081

出　　处：《时间频率学报》2022年第2期110-114,共5页Journal of Time and Frequency

基　　金：国家重点研发计划重点专项(2016YFF0200202);中国计量科学研究院基本科研业务费重点领域资助项目(AKYZD2009)。

摘　　要：喷泉钟驾驭氢钟、晶振等频率源,能够输出标准频率。为了实现上述目标,本文使用自由运转的恒温晶振5 MHz频率输出作为喷泉钟的本振信号,尝试利用喷泉钟锁定恒温晶振。5 MHz本振信号经过倍频和频率综合生成铯原子喷泉钟激励微波源所使用的9.192 GHz的频率信号。喷泉钟使用PI锁定方法,得到此激励微波源的频率信号与铯原子超精细能级跃迁频率信号的差值。为了驾驭恒温晶振,将恒温晶振5 MHz信号经过相位微跃器的调整,锁定至喷泉钟的超精细能级跃迁频率信号。喷泉钟运行周期约为1.5 s,产生一个频率差值。我们使用每5个频率差值计算一个平均频率差值,多个平均频率差值经过局部加权线性回归算法,预估下一个平均频率差值。预估的频率差值经过计算,得到相对频率调整量。计算模拟表明,存在一组合适的计算参数,使得调整后的纸面频率差值数据稳定度大幅提高。使用这种驾驭方法,将得到的相对频率调整量反馈至相位微跃器。实验表明,参考恒温晶振的相位微跃器5 MHz信号频率漂移消失,中长期频率稳定度有极大的改善。The standard frequency signal can be output if the fountain clock steers hydrogen maser or crystal oscillators.In this paper,5 MHz signal of free running oven controlled crystal oscillator(OCXO)is used as the local oscillator(LO)of the fountain clock.The 9.192 GHz signal,generated by frequency synthesizer which references to LO,is used as the interrogation microw ave source of cesium fountain clock.With the software close-loop PI controller,the interrogation microwave signal follows the frequency of the superfine energy level transition of cesium 133 atom(clock transition frequency),and the difference between them is obtained.To steer the OCXO,its frequency needs to be offset by an auxiliary output generator(AOG)and then locked to the clock transition frequency.In one fountain clock cycle,about 1.5 second,the frequency difference between the LO and clock transition frequency is measured.An average frequency difference is calculated by every five measured data.With the local weighted linear regression(L;WLR)algorithm,the following average frequency difference is predicted well by the previous ones.And then,the relative frequency offset value can be calculated by the predicted frequency difference.The calculation simulation shows that there is a set of suitable parameters greatly improving the stability of the adjusted frequency difference data in the paper,U sing this steering method,the relative frequency offset is fed back to the AOG.Experiment result shows,the mid-term and long-term stability of the 5 MHz frequency output of AOG references to the OCXO has improved a lot.

关 键 词：喷泉钟 恒温晶振 驾驭 

分 类 号：TH714[机械工程—测试计量技术及仪器]