浙江农林大学本科生毕业设计（论文）Labview-basedvirtualfunctionSignalGenerator1IntroductionSince1986,theU.S.NI(NationalInstrument)companiestotheconceptofvirtualinstrumentation,alongwithcomputertechnologyandmeasurementtechnology,virtualinstrumenttechnologyhasalsobeendevelopedrapidly.Virtualinstrumentmeans:useoftheexistingPC,withaspeciallydesignedinstrumenthardwareandproprietarysoftware,theformationofthebasicfunctionsofboththeordinaryinstrument,thereareusuallynospecialequipmentfeaturesofthenewinstrument.Comparedwiththetraditionalinstrumentsofitsfeaturesare:bettermeasurementaccuracyandrepeatability;measurementspeed;systemsetuptimeisshort;instrumentfunctiondefinedbytheuser;scalability;technicalupdatesandquick.Virtualinstrumentsoftwareasthecore,thesoftwarecompanyYouyiU.S.NILabviewvirtualinstrumentsoftwaredevelopmentplatformmostcommonlyused.Labviewisagraphicalprogramminglanguage,mainlyusedtodevelopdataacquisition,instrumentcontrolanddataprocessingandanalysissoftware,andpowerful.Currently,thedevelopmentofsoftwareintheinternationaltest,measurementandcontrolindustry,popular,measurementandcontrolareasinthecountryhasalsobeenwidelyused.FunctionGeneratorisascientificresearchandengineeringdesigninawidelyusedgeneral-purposeequipment.ThefollowingfunctionsignalgeneratorwithavirtualdesignanddevelopmentofspecificdescriptionisbasedongraphicalprogramminglanguageLabviewvirtualinstrumentprogrammingandimplementationoftechnology.2virtualfunctionsignalgeneratorstructureandcomposition2.1VirtualFunctionGeneratorfrontpanelThisvirtualfunctionsignalgeneratormainlyconsistsofaPCIbus,multi-functiondataacquisitioncardandappropriatesoftware.TheminstalledonaPCrunningWindows95/98/2000/NTthemachine,shallconstituteapowerfulfunctionofsignalgenerator.ThedesignofthevirtualfunctionsignalgeneratorreferencesignalgeneratorSG1645powerfunctions,frontpanelshowninFigure1.Figure1virtualfunctionsignalgeneratorfrontpanelThefunctiongenerator'sfrontpanelfunctionofthefollowingcomponents:instrumentcontrolbutton,theoutputfr