Design And Realization Of A Multi-channel High Precision Time Interval Analyzer Prototype

In the field of modern measurement,the measurement of time interval is always in the core position.The measurement of many other basic physical quantities needs to be converted into high-precision time interval measurement to complete.The importance of time interval measurement is self-evident.Although there have been extensive theoretical research and many classic commercial instruments in the field of time interval measurement,in recent years,more and more measuring scenes have put forward the requirements of high precision,large range and multi-channel for time interval measurement instruments.Furthermore,it is required that the measuring instruments can have functions such as curve drawing and real-time analysis.In this paper,a multi-channel precision time interval analyzer prototype is designed and implemented by researching of time interval measurement and analysis technology.The main work and innovation points are as follows:1)Analyze and compare the current principle and implementation of high-precision time interval measurement,summarize the technical characteristics of these measurement principles,compare their advantages and disadvantages,and determine the time interval measurement method adopted in this paper,which lays a foundation for the realization of high-precision time interval measurement in the following.2)An 8-channel time interval analyzer engineering prototype is designed and implemented.Based on analyzing and sorting out the general requirements,the overall design of the instrument is carried out:Take a measuring module and an analysis module as the core,man-machine interaction through the touch screen,and stability improvement by using dual power supply is determined.Make the hardware circuit of each module,and write the software program for it.The instrument realizes high-precision time interval measurement of 8 channels,and retains the ability of channel expansion in the structure.It can display and analyze the measurement results in real time,and has the functions of storing and exporting the results.3)In order to further improve the measurement accuracy,a time interval array combination measurement scheme is designed.The front-end circuit structure of measurement is specially designed,and multi-channel time interval measurement is carried out simultaneously with multiple time interval measurement chips.In theory,the random error of the measurement results can be reduced to 1/2 times of the original.At the same time,the iterative solution algorithm and the high-performance microcontroller are used to realize the real-time analysis of the measurement results.Allan variance and Time variance of the measurement results of each channel from 1s to 10 000s can be analyzed in real time.4)A test platform was designed and built for the instrument in this paper.Firstly,all kinds of systematic errors were analyzed and calibrated,and the function verification and performance test of the instrument were carried out.The test results show that,in measuring single channel time interval,the measurement accuracy（STD）for time interval of the instrument is up to 6.34ps,and the measurement range is up to±100s.In the multi-channel measurement,the uncertainty introduced by the inconsistency between channels is better than 13ps after calibration.The short-term stability of time interval measurement can reach 6.36×10^-12@1,and the long-term stability can reach 2.64×10^-13@1000.