Design And Implementation Of The Time Code For High-Precision Fiber-Optic Time Transfer

With the development of science and technology, the high-precision demand oftime transfer is increasing, especially in scientific research, modern advancedequipments and systems, the accuracy and stability of time is essential. Today, amongthe available methods of time transfer, time transmission along optical fibers is oneoption with high-precision, high reliability, high invulnerability and unlimited withdistances. These features will make it become the trend of the future high-precisionground time transfer network.This thesis demonstrates a detailed analysis of high-precision two-way timetransfer along optical fibers, and the design and implementation of the time codesuitable for the optical fiber links.The main works can be divided into the followingthree:（1） This thesis gives an analysis of the main current technologies for timetransfer and a more detailed introduction of the characters, advantages and keyproblems of time transfer along optical fiber links.These can be the theoreticalfoundation for the following work of the system design and implementation.（2） With the consideration of the high speed rate requirement for time transferalong optical fiber links, two kinds of time code improvement scheme based on thestandard IRIG-B(DC) are put forward: IRIG-B(O) and IRIG-B(FSK). The encoder anddecoder for these two scheme are designed and implemented in FPGA, and verified byexperiments.（3） The principle and system error of fiber-optic two-way time transfer areanalyzed, meanwhile, the experiment system is built and performance for the two timecode scheme are tested with good experimental effect. The experimental results showthat these two schemes can achieve stable time transfer with the precision less than100ps on the100km fiber-optic link. （4） Finally, the summary of the present work is given out and the follow-upstudy of fiber-optic time transfer is put forward.