基于FPGA的精密时间测量系统设计

设计了一种在FPGA中基于时间内插技术而实现的高精度时间测量系统。在分析传统数字计数法原理与误差的基础上，从误差源头出发，为精确测量“细”时间即传统数字计数法中待测信号上升沿与下一个计数时钟上升沿的时间差，提出用4个同频、相位依次相差45°的内插时钟测量，通过待测信号上升沿锁存4个内插时钟状态来估算这部分时间差。“粗”时间用高速时钟直接计数，可以保证有大的测量量程，详细分析了该方法测量原理误差。通过实验验证表明，精度高达312.5 ps，误差小于300 ps，该设计具有测量范围大、测量精度高、占用资源少、体积小等优点。

Design of precise time measurement system based on FPGA

High resolution time measurement system was implemented in a single FPGA based on time interpolation. On the basis of analyzing the principle of traditional digital counting method and its error, from the sight of error source, the fine time is the time difference between rising edge of the measured signal and next rising edge of counting clock, in order to measure the fine time accurately, we proposed a method that measures it with 4 interpolation clock signals, which have the same frequency and phase difference of 45 degrees in turn, estimating the fine time by latch clock state at rising edge of the signal to be measured. Meanwhile, a high speed clock is used to measure the coarse time directly. The principle error of this method is discussed in detail. The experimental results show that this method can achieve a precision of 312.5 ps and the error less than 300 ps. The design has advantages of large measurement range, high accuracy, small size, and with less resource.