基于FPGA的时间间隔测量设计与实现

本文主要介绍了一种基于FPGA的高精度时间-数字转换器(TDC)。该TDC在设计上采用了粗计数与细时间测量相结合的技术。粗计数通过高性能的二进制计数器实现,细时间测量利用FPGA的快速进位链实现时间内插。为了改善测量分辨,在设计中借助Wave-Union方法对超大码宽进行了分割。为检验TDC的性能,对其进行了多项测试,获得较好的测试结果。该TDC在大于200ms的动态范围内的时间分辨率小于50ps。微分非线性(DNL)的范围为-1~1.5LSB,积分非线性(INL)的范围为-1.5~1.5LSB。该TDC将应用于In-beam PET影像装置中的飞行时间测量。

Design and Realization of High Precision Time-interval Measurement Based on FPGA

A time-to-digital converter (TDC)with high precision based on field-programmable gate array (FPGA)was presented in this paper.The method combining coarse counting and fine time measurement was adopted in the design.The coarse counting depended on a good performance binary counter and the fine time measurement was realized by using a fast carry chain to implement the time interpolation.For improving measure resolu-tion,the method of Wave-Union was also employed in the design to divide the ultra-wide bin width.Various tests were implemented to check the performance of TDC,and some excellent results were achieved.The test results show that the time resolution (FWHM)of TDC is less than 50 ps within a wide dynamic range greater than 200 ms. The differential non-linearity (DNL)is in the range of - 1-1.5 LSB,and the integral non-linearity (INL)is in the range of -1.5-1.5 LSB.The TDC will be used in In-beam position emission tomography (PET)equipment for time-of-flight measurement.