Research And Application Of High Precision Time Interval Measurement Based On FPGA

Time interval is always used to describe that one event is ahead or behind another event.Precision time interval measurement aims to make time measurement more accurate to the level of microsecond,nanosecond or even picosecond.It has important applications in scientific research,aerospace,satellite navigation,synchronous timing,5G and some other fields.TDC(Time-to-Digital Converter)is a commonly used precision time interval measurement technology.TDC was always implemented in ASIC(Application Specific Integrated Circuit)in earlier time,but its design cost is high,the design cycle is very long and the portability is poor.The realization of TDC in the FPGA(Field Programmable Gate Array)has the advantages of short development cycle,low design cost,and good flexibility.So the realization of FPGA-TDC is of great significance.Through the analysis and comparison of commonly used TDC design schemes and different FPGA chips,the thesis selects the FPGA of Cyclone series,beyond lots of simulates and tests on the two different delay structures(LCELL and Adder dedicated carry chain),and explores calculate the delay time of each unit(LCELL unit 263ps,Adder unit 40ps)to generate high-precision phase shift modules.The whole experiment in this thesis mainly includes "coarse measurement" module and "fine measurement"module.The coarse measurement module is realized by the electronic counting,and the fine measurement module is realized by the tapped delay line composed of dedicated carry chain,and the "thermometer code" obtained from the fine measurement is converted,the sub-stableproblem is solved by the two-level trigger tapping,and the entire tapped delay line structure is measured and verified by the code density test.Through a lot of experimental tests,finally tested that the measurement resolution of the dual-channel measurement system reached 40ps,the measurement accuracy RMS reached 30ps,and the measurement range(0?1)s.These experiments are completed on a single FPGA main control board,which has the advantages of low cost,small size,and good flexibility.