高精度事件计时器的设计与实现

高频率、大范围和高精度是现代卫星/月球激光测距(SLR/LLR)的发展趋势,需要高精度事件计时器作为其时问测量单元.分析研究了事件计时器测量时间的原理,并基于时间数字转换(TDC)和现场可编程门阵列(FPGA)技术,用TDC芯片测量微小时间间隔,同时结合FPGA芯片设计和实现整个高精度事件计时器.进行了信号周期测量实验,结果表明,该测量仪准确度高,标准偏差值优于50 ps,系统误差小于11 ps,量程为24 h,温度漂移小于100 fs/℃,短期稳定性好于±3ps/h.

Realization and Design of High-Accuracy Event Timer

High ranging speed, wide measurement range, and high accuracy are the trends of modern satellite/lunar laser ranging (SLR/LLR) . High precision event timer is demanded as the timing unit in such a laser ranging system. The time interval timing principle of event timer is analyzed.A high-accuray event timer is realized and designed based on time-to-digital converter (TDC) and field programmable gate array (FPGA) technique, for which the TDC chip is used to measure fine time and the FPGA chip is used to measure coarse time and control the whole timing system. Signal period measurement experiment is performed,showing the standard deviation better than 50 ps, the systematic error less than 11 ps, the measurement range of 24 h,the temperature drift below 100 fs/℃, and temporal stability lower than±3 ps/h.