Networked High Precision Time And Frequency Synchronition Of Fixed Nodes

Networked optical fiber time-frequency synchronization technology,which is an extension of point-to-point optical fiber time-frequency synchronization technology,is a time-frequency synchronization technology for ultra-multi-fixed-node systems,which has been developed in recent years.At present,its research is still in its infancy.Networked optical fiber time-frequency synchronization combines the related concepts of networking on the basis of optical fiber time-frequency synchronization.This makes networked optical fiber time-frequency synchronization not only have the advantages of small environmental impact and high transmission accuracy,but also have the advantages of good flexibility and long transmission distance of networked system.The development of this technology can improve the accuracy and flexibility of time-frequency synchronization of super multi-node systems represented by SKA.Taking frequency transmission as the starting point,this paper first introduces the basic theory of time-frequency transmission,including atomic clock model and basic model of optical fiber time-frequency synchronization technology.These basic knowledge is the basis of networked optical fiber time-frequency synchronization technology system.Then,several different classical point-to-point time-frequency synchronization technologies are introduced,including optical fiber bidirectional time-frequency transmission,classical point-to-point time-frequency synchronization scheme and optical fiber time-frequency synchronization multi-point download technology.The basic principles of these basic modes are introduced in detail and the existing problems are pointed out.Then,a networked optical fiber time-frequency synchronization scheme is designed:the influence of environmental factors in transmission process is reduced by pseudo-random code modulation;the energy attenuation in signal transmission is compensated by the design of hierarchical distribution structure,and the number of synchronizable nodes is increased;the operability of the scheme is enhanced by the design of time-frequency synchronization scheme of intra-layer nodes,and then the whole time is improved.The flexibility of the frequency synchronization system and the continuity of the received signal of the relay node are guaranteed by the lossless switching technology of the signal,thus the robustness of the whole time-frequency synchronization system is guaranteed to be improved.Finally,the functional modules of the networked optical fiber time-frequency synchronization system are designed and the corresponding simulation experiments are designed.The experimental results show that the networked optical fiber time-frequency synchronization technology can meet the time-frequency synchronization accuracy requirements of the ultra-multi-node system,and effectively improve the robustness and flexibility of the ultra-multi-node time-frequency synchronization system.