激光测高仪是测量激光脉冲的飞行时间来获得测高仪与探测目标之间的距离，因此激光飞行时间测量的准确性是衡量其系统能力的根本指标。采用了一种专用的时间数字转换芯片设计了时间间隔测量模块，它采用延时线技术，测量频率快，时间分辨率高，受外界环境干扰小，完全适合激光测高的要求。在给出软硬件实现方法的同时，也给出了测量结果。

Pulsed time-of-flight laser altimeter operates by transmitting a short laser pulse to an optical visible target and by detecting the reflected pulse with an optical detector. The measured distance is calculated from this flight time. So the accuracy of laser time interval is a basic beacon to measure its system capability. We use a special time-digital-converter chip to develop a high resolution time interval module. Based on delay chain,it has high frequency and precision,suffer no outside environmental interference,completely suite for laser altimeter. Finally the soft and hardware realization method and measurement result are given.