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基于单片机的数字频率计的设计专业电子信息工程学生姓名冯海洋班级08电子信息工程（1）班学号20080305107指导教师张文洁完成日期目录摘要3前言.....................................................................................................................................5第一章绪论...................................................................................................................................61.1课题背景............................................................................................................................61.2课题研究的目的和意义...................................................................................................61.4数字频率计设计的任务与要求........................................................................................6第二章数字频率计总体方案设计...............................................................................................71.1方案比较............................................................................................................................71.2方案论证............................................................................................................................81.3方案选择............................................................................................................................8第三章数字频率计的硬件系统设计.............................................................................................93.1数字频率计的硬件系统框架...........................................................................................93.2数字频率计的主机电路设计...........................................................................................93.3数字频率计的信号输入电路设计..................................................................................123.4数字频率计显示电路的设计..........................................................................................133.5数字频率计的计数电路的设计......................................................................................153.6数字频率计电源模块的设计..........................................................................................18第四章数字频率计软件系统设计...............................................................................................194.1软件设计规划.................................................................................................................194.1.1信号处理..............................................................................................................194.1.2中断控制..............................................................................................................194.2.1定时器/计数器....................................................................................................204.2.2定时工作方式0...................................................................................................214.3程序流程图设计..............................................................................................................214.3.1主程序流程..........................................................................................................214.3.2中断流程.............................................................................................................23第五章数字频率计的仿真调试...................................................................................................25参考文献.........................................................................................................................................26致谢27附录（程序）.................................................................................................................................28附录：数字频率计的系统原理图.................................................................................................31摘要本方案主要以单片机为核心，主要分为时基电路，逻辑控制电路，放大整形电路，闸门电路，计数电路，锁存电路，译码显示电路七大部分，设计以单片机为核心，被测信号先进入信号放大电路进行放大，再被送到波形整形电路整形，把被测的正弦波或者三角波整形为方波。利用单片机的计数器和定时器的功能对被测信号进行计数。编写相应的程序可以使单片机自动调节测量的量程，并把测出的频率数据送到显示电路显示。本设计以89C51单片机为核心，应用单片机的算术运算和控制功能并采用LED数码显示管将所测频率显示出来。系统简单可靠、操作简易，能基本满足一般情况下的需要。既保证了系统的测频精度，又使系统具有较好的实时性。本频率计设计简洁，便于携带，扩展能力强，适用范围广。[关键词]单片机，运算，频率计，LED数码管AbstractTheprogrammainlymicrocontrollerasthecore,aredividedintotime-basecircuit,thelogiccontrolcircuit,amplifiershapingcircuit,thegatecircuit,thecountingcircuit,latchcircuit,decodingcircuitmostofthesevenshows,designamicrocontrollerasthecore,themeasuredsignalthefirstamplifiertoamplifytheincomingsignal,andthenwassenttothewaveformshapingcircuitsurgery,themeasuredsinewaveortrianglewaveshapingasasquarewave.Counterandtimermicrochipfeaturesofthesignalcount.WritethecorrespondingprogramcanautomaticallyadjustthemeasurementrangeofSCM,andthefrequencyofthemeasureddatatothedisplaycircuitdisplays.Thedesignofthe89C51microcontrollercore,microcontrollerapplicationsandcontrolfunctionsandarithmeticoperationswithLEDdigitaldisplaytubetothemeasuredfrequencyisdisplayed.Systemissimple,reliable,easytooperateandcanbasicallymeetthegeneralneeds.Bothtoensuretheaccuracyofthesystemfrequencymeasurement,butalsothesystemhasgoodreal-time.Thefrequencymeterdesignissimpleandeasytocarry,expansioncapability,wideapplication.[Keywords]microcontroller,operation,frequencymeter,LEDdigitaltube前言在电子测量领域中，频率测量的精确度是最高的，可达10—10E-13数量级。因此，在生产过程中许多物理量，例如温度、压力、流量、液位、PH值、振动、位移、