通信线路故障测试仪设计

吉林化工学院毕业设计说明书通信线路故障测试仪设计TheDesigningofMalfunctionApparatusfortheLinesofCommunication学生学号：04530222学生姓名：黄光浩专业班级：电信0601指导教师：杨明职称：助教起止日期：2010.3.5～2010.6.22吉林化工学院JilinInstituteofChemicalTechnology吉林化工学院毕业设计说明书-I-摘要为了快速准确的找到通讯电缆故障所发生的位置，及时修复故障线路，确保整个通讯网络的安全稳定运行，减少因通讯线路故障带来的经济损失，节省巡线的人力和物力。因此，研究通讯线路故障的测试方法，开发出行之有效的故障检测装置是非常有必要的。本文介绍了一种利用低压脉冲反射法测量通信电缆断点故障位置的方法，及89C51单片机建立电缆断点故障的测距系统。通过该系统控制发射高频脉冲，将脉冲波幅度提高，结合设备载波送入电缆，脉冲波在电缆中传播，遇到高阻的断点、终端点就会发生反射，反射波又经脉冲接收电路到达该系统。在线获取从发射脉冲波开始到接收反射脉冲波为止的时间，计算出电缆断点故障点的准确位置。该系统结构简单、操作简便、测距精度较高、应用效果良好。为了体现设计内容具有现实意义，能够将理论设计应用于实际，在附录中对测距电路主控、发射电路、接收部分电路用Protel99se画了原理图及对接收电路做了PCB设计。关键词：通讯线路；脉冲；故障测试；单片机通信线路故障测试仪设计-II-AbstractInordertofastaccuratethepositionwhichfoundthecommunicationcablefaulttooccur,Thepromptrepairfaultyline,guaranteestheentirecommunicationnetworkthesecuritystablemovement,reduceseconomiclosswhichbecausethecommunicationlinesbreakdownbrings,patrolseconomicalthelinemanpowerandthephysicalresource.Soitisveryimportanttostudyanddevelopaefficaciousoffaultlocationequipment.Themethodofmeasuringthedistanceofbreakpointfaultofcommunicationcablewithlowvoltagepulsereflectionandrelatedsystemestablishedby89C52singlechipcomputeralepresented．Inthissystem，highfrequencypulsesweregeneratedandtheamplitudewereraised．Throughthecarrierofthedevice，thepulsewavewassendingintothecable．Thewavewouldbereflectedwhenitreachedthebreakpointbe．causeofthehighresistance．Thereflectivewavewouldbesentbacktopulsereceivingcircuitinthesystem．Bycalculatingthetimeperiodbe-tweensendingandreceivingofthewave，accuratepositionofthebreakpointcouldbedetermined．Thesystemisinsimpleconstructionandeasyoperation，Itofersprecisedistancemeasurementandexcellentefects.Inordertomanifestthedesigncontenthasthepracticalsignificance,canapplyinactualthetheoreticaldesign，therange-measuringcircuitmastercontrol,thetransmissioncircuit,thereceivepartialelectriccircuitshasbeendrawntheschematicdiagramwithProtel99seintheappendix,andalsothereceivepartialelectriccircuitshasbeenmadethePCBdesign.KeyWords：Communicationlines；Pulse；faulttest；signlechipcomputer吉林化工学院毕业设计说明书-III-目录摘要········································································································IAbstract········································································································II第1章绪论···································································································1第2章通讯线路故障分析················································································22.1通讯线路故障性质分类··········································································22.2通讯线路故障产生的原因·······································································3第3章线路故障探测方法选择·········································································53.1测试方案的选择···················································································53.1.1电桥法·······················································································53.1.2低压脉冲反射法···········································································63.1.3冲击高压闪络法···········································································63.2电缆故障精确定点的方法·······································································73.3方案的选择·························································································7第4章低压脉冲测测试法················································································84.1低压脉冲反射法工作原理·······································································84.2表的格式说明波形比较法判断故障法·······················································94.3内部阻抗平衡技术··············································································104.3.1使用内部阻抗平衡技术的原因······················································104.3.2内部平衡阻抗技术·····································································11第5章系统主控单元硬件电路设计··································································135.1单片机型号的选择··············································································135.2系统辅助单元的硬件选择及电路设计······················································135.2.1信息输入装置············································································135.2.2数码显示输出············································································145.2.3计时单元的选择及硬件电路设计···················································15第6章脉冲发生及接收单元电路设计·······························································166.1脉冲发射电路设计··············································································166.2脉冲接收电路设计··············································································17第7章系统部分软件的设计···········································································227.1主程序设计························································································227.2定时器T0中断子程序设计···································································24通信线路故障测试仪设计-IV-7.3中断0INT中断子程序设计···································································24结论······································································