电子与通信技术专业英语（第6版）课件 项目9 Virtual Instruments

刘骋蔡静主编电子与通信技术专业英语（第6版）高职高专电子信息类“十三五”规划教材EnglishonElectronicandTelecommunicationTechnology02UnitⅡElectronicInstrumentandProductsLesson9VirtualInstruments

UnitⅡNewWordsvirtual ['və:tʃuəl] adj.虚拟的hardware ['hɑ:dweə] n.计算机硬件transform [træns'fɔ:m] v.改变，改观，变换transmit [trænz'mit] v.传输，传送，发送interpreter [in'tə:pritə] n.解释者，翻译器converter [kən'və:tə] n.变换器，换流器，变压器，变频器NewWordsimplementation [,implimen'teiʃn] n.成就，贯彻，安装启用modular ['mɔdjələ] adj. 模块化的monitor ['mɔnitə] n.&vt.显示屏，屏幕，

显示器，监测仪；监视synchronization [,siŋkrənai'zeiʃən] n. 同一时刻，同步NewWordsbus [bʌs] n. 总线Ethernet ['i:θənet] n. 以太网Latency ['leitənsi] n. 潜伏，潜在因素integrate ['intigreit] v. 使一体化，使集成instrumentation [,instrəmen'teiʃən]n. 仪器PhrasesandExpressionsADC（Analogue-to-DigitalConverter） 模数转换器DAC（Digital-to-AnalogueConverter） 数模转换器USBinterface USB接口CPU（CentralProcessingUnit）

中央处理单元scalewith 与……成比例Virtualinstrumentsarecomputerprogramsthatinteractwithrealworldobjectsbymeansofsensorsandimplementfunctionsofrealorimaginaryinstruments.Thesensorisusuallyasimplehardwarethatacquiresdatafromtheobject,transformsitintoelectricsignalsandtransmitstothecomputerforfurtherprocessing（asshowninFig.9-1）.Simplevirtualmeasuringinstrumentsjustacquireandanalysesdata,butmorecomplexvirtualinstrumentscommunicatewithobjectsinbothdirections.Lesson9VirtualInstrumentsChineseTranslationofTexts虚拟仪器是通过传感器与真实世界物体进行交互并完成真实或虚拟仪器功能的计算机程序。传感器通常是一个简单的硬件，它从实物获取数据，将其转换成电子信号并传输到计算机作进一步处理（如图9－1所示）。简单的虚拟测量仪器只是获取和分析数据，但更复杂的虚拟仪器能与物体进行双向通信。第9课

虚拟仪器ChineseTranslationofTextsRealworldsignalsareofanaloguenature,whileacomputerisadigitalinstrument;thereforethecomputerneedsalsointerpreters–analogue-to-digitalanddigital-to-analogueconvertersforcommunicationwiththeobject.ADCandDACboardsthatimplementthisfunctionininexpensivesystemsareusuallyplacedinsidethecomputer.CompactexternalADC/DACconverterswithUSBinterfacearealsobecomingpopular.ChineseTranslationofTexts现实世界的信号是模拟性质的，而计算机是数字仪器；因此计算机与对象进行通信时需要进行转译——模-数和数-模转换。在廉价的系统中，实现这一功能的模数转换和模数转换板通常内置于计算机中。紧凑的外置带USB接口的模数/数模转换器的也越来越普及。ChineseTranslationofTextsLabVIEWisagraphicalprogramminglanguagefromNationalInstruments.LabVIEWprogramsarecalledvirtualinstrumentsoftenabbreviatedtoVIs.Eachvirtualinstrumenthastwocomponents,ablockdiagramandafrontpanel.Controlsandindicatorsonthefrontpanelallowanoperatortoinputdataintoorextractdatafromanalreadyrunningvirtualinstrument.ChineseTranslationofTexts

LabVIEW是NI公司的图形化编程语言。通常把LabVIEW程序称为虚拟仪器，缩写为VIs。每个虚拟仪器有两个组成部分，框图和前面板。前面板上的控制和指令允许操作员从一个已经在运行的虚拟仪器中输入数据或提取数据。ChineseTranslationofTextsIntermsofperformance,LabVIEWincludesanactualcompilerthatproducesnativecodefortheCPUplatform,sothegraphicalcodeiscompiled,ratherthaninterpreted.ChineseTranslationofTexts在性能方面，LabVIEW包含一个为CPU平台生成本地代码的实际的编译器，它编译图形代码，而不仅仅是转换。ChineseTranslationofTextsOneofthemainbenefitsofLabVIEWisthatpeoplewithlittleornopreviousprogrammingexperienceareabletoaccesshardwareinput/outputmorerapidlyandthroughahardwareabstractionsystem.Thisabstractionallowsisolationbetweenhardwareimplementationandsoftwaresolution.AtechniquewhichwithoutNationalInstrumentssoftwaredriverinterfacewouldbeextremelytimeconsuming.ChineseTranslationofTexts

LabVIEW的主要优点之一是，有很少的或者根本没有编程经验的人都能够很迅​​速地访问硬件的输入/输出，以及通过硬件抽象系统。这个硬件抽象层允许硬件实现和软件解决方案之间的隔离。没有NI软件驱动程序接口的技术将是非常费时的。

ChineseTranslationofTextsAnothervirtualinstrumentationcomponentismodularI/O,designedtoberapidlycombinedinanyorderorquantitytoensurethatvirtualinstrumentationcanbothmonitorandcontrolanydevelopmentaspect.Usingwell-designedsoftwaredriversformodularI/O,engineersandscientistsquicklycanaccessfunctionsduringconcurrentoperation.ChineseTranslationofTexts另一个虚拟仪器组件是模块化的I/O，它被设计用来在任何命令或数量上迅速兼容，以确保虚拟仪器可以同时监视和控制各个方面的发展。使用为模块化的I/O精心设计的软件驱动程序，工程师和科学家可以在并行操作期间实现快速访问功能。ChineseTranslationofTextsThethirdvirtualinstrumentationelement–usingcommercialplatforms,oftenenhancedwithaccuratesynchronization–ensuresthatvirtualinstrumentationtakesadvantageoftheverylatestcomputercapabilitiesanddatatransfertechnologies.Thiselementdeliversvirtualinstrumentationonalong-termtechnologybasethatscaleswiththehighinvestmentsmadeinprocessors,buses,andmore.ChineseTranslationofTexts虚拟仪器的第三个要素——使用商业平台，这通常使得精确同步得到提高——确保该虚拟仪器采用了最新的计算机功能和数据传输技术。这个元素保证了虚拟仪器在高投资规模的处理器，总线技术上的技术水平。ChineseTranslationofTextsVirtualinstrumentationsystemsfrequentlyuseEthernetforremotetestsystemcontrol,distributedI/O,andenterprisedatasharing.Ethernetprovidesalow-cost,moderate-throughputmethodforexchangingdataandcontrolcommandsoverdistances.However,duetoitspacket-basedarchitecture,Ethernetisnotdeterministicandhasrelativelyhighlatency.Forsomeapplications,suchasinstrumentationsystems,thelackofdeterminismandhighlatencymakeEthernetapoorchoiceforintegratingadjacentI/Omodules.ThesesituationsarebetterservedwithadedicatedbussuchasPXI,VXI,orGPIB（asshowninFig.9-2）.ChineseTranslationofTexts虚拟仪器系统在进行远程测试系统控制，分布式I/O和企业数据共享时，经常利用以太网。以太网为数据交换和远距离指令控制提供了一个低成本和中等吞吐量的方法。然而，由于其基于分组的架构，以太网具有不确定性，并有较高的延迟。对于某些应用，如仪表系统，由于以太网缺乏确定性和高延迟，使其在集成相邻的I/O模块时不是一种好的选择。这种情况下最好选择专用总线，如PXI，VXI或GPIB（如图9-2所示）。ChineseTranslationofTextsNotesVirtualinstrumentsarecomputerprogramsthatinteractwithrealworldobjectsbymeansofsensorsandimplementfunctionsofrealorimaginaryinstruments.

realworldobjects：真实世界物体，现实世界中的物体。虚拟仪器是通过传感器与真实世界物体进行交互并完成真实或虚拟仪器功能的计算机程序。1NotesRealworldsignalsareofanaloguenature,whileacomputerisadigitalinstrument.Realworldsignals：现实世界的信号现实世界的信号是模拟信号，而计算机是数字仪器。2Notesthereforethecomputerneedsalsointerpreters–analogue-to-digitalanddigital-to-analogueconvertersforcommunicationwiththeobject.

analogue-to-digital：模拟-数字，从模拟到数字

digital-to-analogueconverter：数字-模拟转换器因此计算机与对象进行通信时需要进行转译－模数转换和数模转换，与被测对象进行通信。3NotesLabVIEWisagraphicalprogramminglanguagefromNationalInstruments.LabVIEWprogramsarecalledvirtualinstrumentsoftenabbreviatedtoVIs.LabVIEW：是美国国家仪器公司（NationalInstrumentsNI）1986年推出的图形化系统设计软件，现今，数以百万的工程师和科学家可以使用LabVIEW来构建他们的测试、测量与控制系统。Vis：virtualinstrument虚拟仪器技术就是利用高性能的模块化硬件，结合高效灵活的软件来完成各种测试、测量和自动化的应用。

LabVIEW是NI公司的图形化编程语言。通常把LabVIEW程序也称为虚拟仪器，缩写为VIs。4NotesAnothervirtualinstrumentationcomponentismodularI/O.

I/O：input/output的缩写，即输入输出端口。另一个虚拟仪器组件是模块化的I/O。5NotesThesesituationsarebetterservedwithadedicatedbussuchasPXI,VXI,orGPIB.PXI：(PCIextensionsforInstrumentation，面向仪器系统的PCI扩展)是一种坚固的基于PC的测量和自动化平台。VXI：CiscoVirtualizationExperienceInfrastructure虚拟化体验基础架构GPIB：GeneralPurposeInterfaceBus通用接口总线这种情况下最好选择专用总线，如PXI，VXI或GPIB。6Exercises1.WriteT(True)orF(false)besidethefollowingstatementsaboutthetext.a.Thesensorisusuallyasimplesoftwarethatacquiresdatafromtheobject,transformsitintoelectricsignalsandtransmitsittothecomputerforfurtherprocessing.b.Realworldsignalsareofdigitalnature,whileacomputerisaanalogueinstrument.c.ADCandDACboardsthatimplementthisfunctioninexpensivesystemsareusuallyplacedinsidethecomputer.d.LabVIEWisagraphicalprogramminglanguagefromNationalInstruments.e.Controlsandindicatorsonthefrontpanelallowanoperatortoinputdataintoorextractdatafromanalreadyrunningvirtualinstrument.Exercises1.WriteT(True)orF(false)besidethefollowingstatementsaboutthetext.a.Thesensorisusuallyasimplesoftwarethatacquiresdatafromtheobject,transformsitintoelectricsignalsandtransmitsittothecomputerforfurtherprocessing.b.Realworldsignalsareofdigitalnature,whileacomputerisaanalogueinstrument.c.ADCandDACboardsthatimplementthisfunctioninexpensivesystemsareusuallyplacedinsidethecomputer.d.LabVIEWisagraphicalprogramminglanguagefromNationalInstruments.e.Controlsandindicatorsonthefrontpanelallowanoperatortoinputdataintoorextractdatafromanalreadyrunningvirtualinstrument.F

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,andmore.Exercises2.Fillinthemissingwordsaccordingtothetext.a.Virtualinstrumentsarecomputerprogramsthatinteractwithrealworldobjectsbymeansofsensorsandimplementfunctionsofrealorimaginaryinstruments.b.LabVIEWprogramsarecalledvirtualinstrumentsoftenabbreviatedtoVIs.c.Thisabstractionallowsisolationbetweenhardwareimplementationandsoftwaresolution.d.Ethernetprovidesalow-cost,

moderate-throughputmethodforexchangingdataandcontrolcommandsoverdistances.e.Thiselementdeliversvirtualinstrumentationonalong-termtechnologybasethatscaleswiththehighinvestmentsmadeinprocessors,buses,