Research On Technologies For High Precision Time And Frequence Referency Transmission By Optical Fiber

Time-frequency reference transfer technology is widely used in aerospace,measurement and control and other scientific fields,while using optical fiber to transmit time-frequency reference is an important transmission method which makes full use of the advantages of low loss,low noise and stable transmission of optical fiber,thereby achieving high-precision and high-stability time-frequency reference transmission.Based on the existing research on time-frequency standards fiber transfer technology,we have designed and implemented a high-precision time-frequency standards fiber transmission scheme,then tested and verified it.We have mainly done the following work:The first part is analysis on existing research on time-frequency standards fiber transfer technology and application scenarios of this article.We took the clock and time synchronization between the RF transceiver unit in the distributed multiple input multiple output?MIMO?system as the application scenario,and analyzed the system's requirements for the transmission accuracy and stability of the time and frequency reference signals.We analyzed the effect of temperature on the signal transmission delay in the optical fiber,and then selected the single fiber bidirectional transmission mode with the same wavelength.According to the requirements of transfer accuracy and stability,we analysized the data accuracy in the phase measurement and compensation process,and the main index when selecting the constant temperature crystal oscillator?OCXO?and its control digital-to-analog converter?DAC?.The second part is research about the key technologies for fiber-optic based time and frequency standards transfer.We studied the single-fiber bidirectional same-wavelength compensation mode in detail,and designed a phase difference measurement algorithm and a method for phase difference compensation of electrical signals in the digital domain in the compensation system for frequency signals in sinusoidal form.We conducted a simulation test on the digital phase-locked loop in the remote-end frequency signal recovery device to provide debugging basis for the actual hardware measurement.Finally,we combined with the frequency signal recovery method,designed a time-frequency reference simultaneous transfer method that embeds the time signal into the frequency signal waveform.Finally,we implemented and tested the fiber-optic based time and frequency standards transfer technology designed in this paper.Implemented some digital signal processing function using software radio platform and described the implementation method and architecture of key modules in detail.Built a hardware platform for testing and verification according to design principles.in the 10km optical fiber transmission test,when the temputure kept room temputure?18??,phase difference error of frequency signal did not exceed?5.5 ps,when the temperature changes from-30?to+40?at a rate of 0.5?/min,phase difference error of frequency signal did not exceed ps.During a test in the natural environment for a whole day,stability of frequency signal achieved1.44?10^-14at 1000s-average.This paper presents a high-precision optical fiber time-frequency standard transfer technology solution,which was verified through theoretical analysis and hardware test.It has engineering reference significance in the development of time-frequency standard transfer technology.