摘要近年来，我国科技发展日新月异，电缆发挥着越来越重要的作用，对于电缆长度测量的准确性，快速性，要求越来越高。

导线长度测量研究，目前已经取得一定成果，但大多难以广泛应用。本文设计的基于脉冲反射法电缆长度测量系统，既保证了测量精度，又节省时间，降低了测量成本，具有广阔的应用前景。该系统的另一个用途是电缆断线故障定位，将故障及时排除。61183

本论文首先比较几种常用电缆长度测量方法的优缺点后，最终选取了脉冲反射法测量电缆长度，并设计实验验证测量精度。

其次，设计了1.2GHz高频脉冲发生电路，作为计数法测量时间间隔的时钟基准。

再次，设计了高速计数电路，经过电平转换和计数芯片串联等方式计数1.2GHz的高频模拟脉冲

最后，用完整的实验装置测量了几种长度的导线，观察实验数据，证明了设计符合要求。

毕业论文关键词   脉冲反射法 故障定位 高频脉冲

毕业设计说明书（论文）外文摘要

Title  Cable length measurement based on pulse reflection method

Abstract In recent years, China's rapid advancement in technology, the cable is playing an increasingly important role, the cable length measurement accuracy, rapidity, increasingly demanding.

Wire length measurement studies, has made some achievements, but most difficult widely used. This design is based on pulse reflection method cable length measuring system, both to ensure accuracy, but also saves time and reduces the cost of measurement, and has broad application prospects. Another use of the system is the cable disconnection fault location, the fault immediately removed.This paper first compares several common advantages and disadvantages of cable length measurement methods, the final selection of the pulse reflection measurement cable length and design experiments validate the measurement accuracy.Secondly, the design of 1.2GHz frequency pulse generating circuit, the time interval measured as the count clock reference.Again, the design of high-speed counting circuit, after the chip level conversion and counting, etc. series of high-frequency analog pulse counting 1.2GHz.Finally, the complete experimental device measuring the length of the wire several observed experimental data prove that the design meets the requirements.

Keywords fault location frequency pulse pulse reflextion methode

1．绪论 6

1.1课题的来源和背景 6

1.2 测距方法发展现状 6

2．系统总体设计 10

2.1总体设计 10

2.2高精度时间间隔测量模块设计 12

2.3单片机系统设计 12

2.3.1调试接口 13

2.3.2 系统时钟 13

2.3.3 I/O接口 14

2.3.4 模拟数字转换（ADC） 15

2.3.5 串行接口 15

3．电路设计 17

4．软件设计 24

4.1开发环境 24

4.2系统主程序 25

4.3数字滤波技术 25

5．实验数据及分析 27

5.1调试过程 27

5.2实验数据 27