简易数字频率计硬件设计（转载）摘要在当今社会，随着电子计算机计算机、通讯设备、音频视频等的使用，频率计也越来越频繁的被使用，频率计的发展也变得尤为重要。频率计是一种基本的测量仪器，是用数字显示被测信号频率的仪器，被测信号可以是正弦波，方波或其它周期性变化的信号。因此，它被广泛应用与航天、电子、测控等领域。它的基本测量原理是，首先让被测信号与标准信号一起通过一个闸门，然后用计数器计数信号脉冲的个数，把标准时间内的计数的结果，用锁存器锁存起来，最后用显示译码器，把锁存的结果用LED数码显示管显示出来。在实际上的硬件设计用到的器件较多，连线也比较复杂，而且会产生比较大的延时，造成测量误差、可靠性差。随着复杂可编程逻辑器件（CPLD）的广泛应用，以EDA工具作为开发手段，运用VHDL语言，将使整个系统大大简化，提高整体的性能和可靠性。数字频率计是最基本的参数之一，并且与许多电参量的测量方案、测量结果都有十分紧密的联系，因此频率的测量就显得更为重要。频率计测频有两种方式：一是直接测频法；二是间接测频法。本次设计的内容是一款基于8位单片机AT89C51的测频系统该装置由输入部分与显示部分组成，输入部分可以收到发射机送来的信号，并通过单片机再传到显像管。此系统具有测量频率和带宽等功能。关键词：频设计的率计，直接侧频法，间接测频法，单片机AT89C51Simpledigitalfrequencymeter'shardwaredesignAbstractInthesociety,alongwiththeelectronicaccountingmachinecomputer,thecommunicationequipment,theaudiofrequencyvideofrequencyandsoonuse,thefrequencymeteralsomoreandmorefrequentisusednow,frequencymeter'sdevelopmentalsobecomesespeciallyimportant.Thefrequencymeterisonekindofbasicmeteringequipment,iswiththedigitdemonstratedthatwasmeasuredthesignalingfrequencytheinstrument,wasmeasuredthesignalmaybethesinewave,thesquare-waveorotherperiodicvariationsignal.Therefore,itiswidelyappliedanddomainsandsoonastronautics,electron,observation.Itspreliminarysurveyprincipleis,firstletsmeasurethatthesignalandthestandardsignalthroughastrobe,thenwiththecountercountingsignalpulse'sinteger,standardtime'sincounting'sresult,savetogetherwiththelatchlock,finallyusestodemonstratethedecoder,savestheresultthelocktodemonstratewiththeLEDnumericalcodedisplaytube.Thecomponentwhichusesinthehardwaredesigninfactaremany,thesegmentisalsoquitecomplex,willhavethequitebigtimedelay,willcausethemeasuringerror,thereliabilitytobebad.Alongwithcomplexprogrammablelogicalcomponent(CPLD)thewidespreadapplication,takesthedevelopmentmethodbytheEDAtool,utilizestheVHDLlanguage,willcausetheoverallsystembigsimplification,enhancesthewholetheperformanceandthereliability.Thedigitalfrequencymeterisoneofmostbasicparameters,andwithmanyelectricityparameter'ssurveyplan,themeasurementresulthasclosecontacting,thereforethefrequencysurveyappearsmoreimportant.Thefrequencymeterfrequencymeasurementhastwoways:First,directfrequencymeasurementlaw;Second,indirectfrequencymeasurementlaw.Thisdesign'scontentisonesectioniscomposedbasedon8monolithicintegratedcircuitAT89C51frequencymeasurementsystemthisequipmentbytheinputsectionandthedemonstrationpart,theinputsectionmayreceivethesignalwhichthetransmittersends,andpassestotheteletronagainthroughthemonolithicintegratedcircuit.Thissystemhasfunctionsandsoonsurveyfrequencyandbandwidth.Keyword:Frequencydesignrateidea，Directsidefrequencylaw，Indirectfrequencymeasurementlaw，MonolithicintegratedcircuitAT89C51目录第1章绪论..................................................................11.1研究背景.............................................................11.2研...
