Research And Implementation Of High Precision Function Signal Transmission Based On Fiber

Function signals are becoming more and more important in modern engineering applications with the development of electronic technology,which are widely used in testing,communications,military and other fields.In some cases,the function signals of each terminal station need to be coherently consistent,and the most direct way to achieve this coherence is to implement function signal transmission between sites.The transmission of existing function signals is basically limited in the field of electricity,and the research on high-stability and long-distance transmission technology of function signals is still in a relatively blank state due to factors such as wire attenuation and electrical noise.Optical fiber is an excellent transmission medium,which has the characteristics of small transmission attenuation,frequency bandwidth,and less susceptible to interference,which can meet the needs of long-distance function signal transmission.At present,the technology of using fiber to transmit optical carrier microwave signals has a certain research foundation,so the use of optical fiber as the transmission medium of function signals is highly feasible.In view of the characteristics of function signals and the superiority of optical fiber transmission,this thesis conducts in-depth research on high-precision fiber function transmission methods,proposes high-order harmonic phase compensation technology,designs and builds a high-precision function signal transmission system based on optical fiber,realizes long-distance and high-stability transmission of function signals,and enriches the application scenarios of function signals.The main research work and results of this thesis are as follows:1.This thesis studies the principle and mechanism of external interference of optical carrier function signals in optical fiber transmission,analyzes the phase disturbance caused by temperature,vibration and other major factors,and proves the necessity of phase compensation structure in optical fiber transmission system.The differences between optical fiber frequency transmission and function signal transmission are analyzed,and after traversing the existing phase compensation methods,the active optical phase compensation method that adjusts the transmission optical path is selected to ensure the stability of function signal transmission.2.In this thesis,a signal transmission scheme of optical fiber function based on the high-order harmonic phase compensation method is proposed with the standard phase-locked loop structure,and the design and implementation of the hardware circuit structure and phase compensation algorithm are completed.The hardware structure includes hardware function components of each part of the transmission system from arbitrary waveform module,optical fiber transmission structure,phase recognition module,phase compensation module to output conditioning module,and the phase compensation algorithm based on fuzzy PI control according to the hardware structure design of the phase compensation module is completed.3.In this thesis,an experimental platform for high-precision function signal transmission based on fiber is built,and several experiments are carried out.In this experiment,a continuous laser with a wavelength of 1550nm is used to realize the transmission of 20MHz function signals in a 10km fiber link,and the time domain and frequency domain indicators of the recovery signal at the receiving end and the frequency stability of transmission are analyzed.The experimental results show that under the condition of the phase compensation module,the RMS value for transmission jitter of the square wave signal transmitted by the system is about 31ps,the frequency stability is2.4×10^-11 at 1s,and it can reach 4.2×10^-12at 1000s.This performance specification meets the needs of most real-world function wave coherence.