Fiber Based Time and Frequency Synchronization System
We build up a time and frequency synchronization system via the 80 km urban fiber link between Tsinghua University and the National Institute of Metrology in Changping city. Using the system, we demonstrate simultaneous time and RF signal distribution via
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Fiber Based Time and Frequency Synchronization System Bo Wang, Chao Gao, Weiliang Chen, Yu Bai, Jing Miao, Xi Zhu, Tianchu Li and Lijun Wang
Abstract We build up a time and frequency synchronization system via the 80 km urban fiber link between Tsinghua University and the National Institute of Metrology in Changping city. Using the system, we demonstrate simultaneous time and RF signal distribution via optical fibers. The measured frequency dissemination stability of a 9.1 GHz RF signal is 7 9 10−15/s, 5 9 10−19/day, and the measured time synchronization accuracy is 50 ps. Relevant results were published on the Scientific Reports of Nature Publishing Group. To further build up a regional time and frequency network, integrated-designed modules are needed. Its long term continuous running stability and commonality should be tested. In this paper, we introduce the design of the frequency dissemination modules. After 135 days’ continuously running, we get the million-second frequency dissemination stability of 8 9 10−19/106 s. We also introduce our multiple-access download module, which improves the frequency dissemination scheme from the traditional point to point protocol to be a tree structure protocol, and greatly improves its applicability. Using it, the stability of the receiving frequency signal at arbitrary accessing point is almost 4 orders of magnitude better than that using directly accessing method. All of these modules will be applied to build up the regional time and frequency network. B. Wang (&) C. Gao Y. Bai J. Miao X. Zhu T. Li L. Wang Joint Institute for Measurement Science, Tsinghua University, Beijing 100084, China e-mail: [email protected] B. Wang L. Wang The state key lab of precision Measurement Technology and Instrument, Department of Precision Instruments, Tsinghua University, Beijing 100084, China C. Gao Y. Bai J. Miao X. Zhu L. Wang Department of Physics, Tsinghua University, Beijing 100084, China W. Chen T. Li L. Wang National Institute of Metrology, Beijing 100013, China
J. Sun et al. (eds.), China Satellite Navigation Conference (CSNC) 2013 Proceedings, Lecture Notes in Electrical Engineering 245, DOI: 10.1007/978-3-642-37407-4_32, Ó Springer-Verlag Berlin Heidelberg 2013
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Keywords Time Multiple-access
B. Wang et al.
Frequency Dissemination Synchronization Stability
32.1 Introduction With the definition of second changing from astronomical second to atomic second, in order to measure and further improve the accuracy of atomic second, a regular time and frequency comparisons between atomic clocks located in different locations are required. These requirements give birth to a new research directionsprecise time and frequency synchronization [1]. More importantly, precise time and frequency synchronization has important applications in navigation systems. In the satellite based global positioning systems (such as COMPASS, GPS, and GLONASS), the entire system shares one common clock frequency and one common highly synchronized system t
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