Design And Realization Of Multi-channel Time-interval Counter

In the field of measurement,the time-interval measurement is extremely widely used.For example,the measurement of physical quantities such as distance,capacitance and temperature,etc can be converted into time-interval measurement by some method.Thus,if the time-interval measurement is more accurate,it is possible to achieve a more accurate measurement of physical quantities such as distance,capacitance,temperature,etc.Therefore,most fields require high precision for timeinterval measurement.With the development of science and technology,more and more fields need not only high-precision time-interval measurement,but also multi-channel time-interval measurement technology.In high-energy physics,navigation and positioning,laser ranging and many other scientific research and engineering applications,multi-channel time-interval measurement technology can simplify operation and improve test efficiency and accuracy.Therefore,the time-interval measurement technology with high precision and multiple channels has become a research hotspot.Although the current research on multi-channel time-interval counters has made great achievements,there is still few mature devices on the market.The research of multi-channel time-interval counter still has great market value and research significance.This paper designs and implements a multi-channel time-interval counter based on FPGA and TDC-GP22 chip.The main research contents and results are as follows:1.The time-interval measurement methods commonly used at this stage are analyzed and studied.From the aspects of resolution,range and hardware implementation,this paper is based on the FPGA chip using the pulse filling method for "rough measurement",based on the TDC-GP22 chip for "fine measurement",the combination of the two chips to achieve the time-interval measurement with high resolution,large range and multi-channel.2.The programming and simulation of FPGA algorithm in the multi-channel time-interval counter are completed,and the host computer software is designed.The algorithm is implemented for the tasks required by the FPGA.The ergodicity test of the program by ModelSim proves the feasibility and correctness of the program design.Based on the LabWindows/CVI platform,the host computer software is designed to realize the functions of displaying,storing and analyzing the measurement results,and optimizing the interaction between the multi-channel time-interval counter and the user.3.A test platform was built to verify the function and performance of the multichannel time-interval counter.Through the test platform,the instrument was tested on the whole machine to verify the functional integrity.And the source of the instrument measurement error was analyzed and calibrated,and the influence of time-base performance on measurement was studied.When using the on-board crystal oscillator to provide the working clock,the accuracy of the measurement will gradually deteriorate as the interval to be tested increased,and the short-term stability is better than 75ps@100s.After using the UTC(NTSC)main clock to tame the crystal oscillator,the accuracy is always within 500 ps,the accuracy of the measurement result is always within 500 ps,the short-term stability is keeping within 150ps@100s and the long-term stability is keeping within 150ps@12h.And the channel consistency remains within 200 ps.