电子信息与通信工程专业英语lesson5(太原理工大学版).ppt

2020 3 18 可编辑 Chapter5Communication第5章通信 1 2020 3 18 可编辑 5 1AShortHistoryofCommunication通信简史5 2WirelessCommunicationTechnology无线通信技术5 3OpticalFiberCommunication光导纤维通信 2 2020 3 18 可编辑 5 4BasicNetworkingConceptsforComputerNetwork应用于计算机网络的基础网络概念 3 2020 3 18 可编辑 TEXT文章5 1AShortHistoryofCommunication 1 Originaltechnologiesofcommunication2 Communicationatthespeedofelectricity 4 2020 3 18 可编辑 convergencen 集中 收敛 融合couriern 送快信的人 旅行从仆circuitswitching电路交换cyberterrorismn 网络dot comsn 网络企业ecommercen 电子商务heliographn 日光仪 5 2020 3 18 可编辑 InterfaceMessageProcessorsn 接口信息处理机messageswitching报文交换monopolyn 垄断semaphoren 信号灯shacklevt 束缚skepticsn 怀疑学派sabbaticaln 学术假期Telenetn 远程通信网Telecopiern 远程复印机 6 2020 3 18 可编辑 Nomatterwhatcareeryouenter you llneedtocommunicatewithpeople Webelievethatcultural social andpersonalexperienceimprovesthroughmoreeffectiveunderstandingandpracticeofcommunication CommunicationStudiesseektounderstandcommunicationandtoimproveitspracticeinavarietyofrelationships 7 2020 3 18 可编辑 Wefocusontwopersonandfamilycommunication communicationinsmallgroupsandinlargeorganizations communicationacrosscommunities thenatureoflanguageandsymbols andthenatureofargumentandpersuasioninpoliticalsettingsandinsocialmovements 8 2020 3 18 可编辑 Thehistoryofcommunicationcangobacktothousandsofyears However thetechnologiesthatsomanyofusareaddictedtotoday mobilephones theinternet satelliteTV arebuiltonourachievements 9 2020 3 18 可编辑 Eachnewdevelopmenthastransformedtheworldwelivein Anunderstandingofthejourneywehavetakentogetwherewearenowshowsthattoday stechniquesarerefinementsofwhatcamebefore Reallybigrevolutionsmaybestilltocome 10 2020 3 18 可编辑 1 Originaltechnologiesofcommunication Communicationbeginswiththefirstconversationsbetweenpeople Fireandthesmokeitproducesmayalsohavebeenusedforsimplecommunicationbetweenseparatedgroups 11 2020 3 18 可编辑 TheinventionoftheprintingpressinChinasometimeafter300ADmeantthatthesamemessagecouldbedeliveredtomanypeoplecheaplyandmorequicklythancopyingoutthemessagemanytimesbyhand 12 2020 3 18 可编辑 2 Communicationatthespeedofelectricity Withthediscoveryofelectricitythespeedandrangeofcommunicationonceagainbegantoincrease 13 2020 3 18 可编辑 TheinventionoftechniquessuchasMorsecodeallowedcomplexmessagestobetransferredatveryhighspeedsoverthisnewmedium Thesehadhugerepercussionsformanyaspectsofhumanlife forexample transportcouldbebettercoordinated governmentcouldtransmitdecisionstodistantofficesalmostinstantaneously andbusinessescouldworkwithmorebusinessesoverlargerdistances 14 2020 3 18 可编辑 Thefirstamplitudemodulation AM radiostationbeganoperatinginSpringfield Mass shortlyafterWorldWarI andthefirstfrequencymodulation FM stationwasauthorizedtooperatebytheFederalCommunicationsCommission FCC in1940 15 2020 3 18 可编辑 ThefirsttelevisionstationwasauthorizedbytheFCCin1941andthefirstCATVstationsystembeganseveralyearslater 16 2020 3 18 可编辑 SeeTable5 1Electricalcommunicationhistory 17 2020 3 18 可编辑 Atthesametimeasthesedevelopmentsinsound peoplewereworkinghardoncapturingimages Forhundredsofyearsartistsandscientistshadknownthatasmallholeinthewallofadarkenedroomwouldprojectanimageoftheoutsideworldontheoppositewall 18 2020 3 18 可编辑 In1814JosephNic phoreNi pceusedthisprincipletoprojectanimageoftheworldontochemicallytreatedpaperinabox sothefirstphotographhadbeentaken Imagesfromonepartoftheworldcouldbebroughttoanother 19 2020 3 18 可编辑 ThisallowedpeopleinTanzaniatoseewhataLondonStreetlookedlike andpeopleinLondontomarvelatMaasaiwarriorsdressedintheirfinery In1877 EadweardMuybridgedevelopedacamerawhichcouldtakeaseriesofphotographsinrapidsuccession 20 2020 3 18 可编辑 Hedidthisinordertowinabetonwhetherallahorseshoovesleftthegroundwhenitran Helostthebet butinventedthemoviecamera By1927thishadbeencombinedwithrecordedsound allowingpeopletosharerealisticexperiencesaroundtheworld 21 2020 3 18 可编辑 Thetechnologiesthatwehavediscussedhaveallhelpedusstoreandtransmitcommunication Allthesetechnologiesarejoiningtogetherintheformofcomputersandtheinternet 22 2020 3 18 可编辑 5 2WirelessCommunicationTechnology 1Introduction2 Wirelesscommunicationtechnology 23 2020 3 18 可编辑 In1895 Guglielmo Marconiopenedthewayformodernwirelesscommunicationsbytransmittingthethree dotMorsecodefortheletter S overadistanceofthreekilometersbyelectromagneticwaves 24 2020 3 18 可编辑 IntroductionTherearetwofundamentalaspectsofwirelesscommunicationthatmaketheproblemchallengingandinteresting 25 2020 3 18 可编辑 Firstisphenomenonoffading thetimevariationofthechannelstrengthsduetothesmall scaleeffectofmultipathfadingandshadowingbyobstacles Second wirelessuserscommunicateovertheairandthereissignificantinterferencebetweenthem 26 2020 3 18 可编辑 Theinterferencecanbebetweentransmitterscommunicatingwithacommonreceiver betweensignalsfromasingletransmittertomultiplereceivers orbetweendifferenttransmitter receiverpairs 27 2020 3 18 可编辑 Howtodealwithfadingandinterferenceiscentraltothedesignofwirelesscommunication 28 2020 3 18 可编辑 Therearemanywirelesscommunicationstechnologiesthatcanbedifferentiatedbyfrequency bandwidth range andapplications 29 2020 3 18 可编辑 Thesecategoriesrangefromwirelesswideareanetworks WWANs whichcoverthewidestgeographicarea towirelesspersonalareanetworks WPANs whichcoverlessthan10meters 30 2020 3 18 可编辑 2 WirelesscommunicationtechnologyWPAN AWPANisapersonalareanetwork anetworkforinterconnectingdevicescenteredaroundanindividualperson sworkspace inwhichtheconnectionsarewireless 31 2020 3 18 可编辑 communicationwithinabout10metersusedmainlyascablereplacementtechnologiesfordatasynchronizationandconnectivityfordevicesthatareclosetoeachother 32 2020 3 18 可编辑 BluetoothwirelesstechnologyistheprevalentWPANtechnologytoday Itoperatesinthe2 4 GHzunlicensedfrequencyband Ultra wideband UWB technologyprovideshighbandwidthbytransmittingatverylowpoweracrossabroadfrequencyspectrum 33 2020 3 18 可编辑 WirelessLANs AWireLAN WLAN whichsometimesreferredtoasLAWNrobustwirelessnetworkconnectivityoveralocalareaofapproximately100metersoperatesinthe2 4 GHzfrequencybandat11Mbps 34 2020 3 18 可编辑 802 11standardsusetheEthernetprotocolandCarrierSenseMultipleAccesswithCollisionAvoidance CSMA CA forpathsharingandincludeanencryptionmethod theWiredEquivalentPrivacyalgorithm 35 2020 3 18 可编辑 WiFifocusonuserauthenticationandencryptionMultiple InputMultiple Output MIMO radiofrequency RF 36 2020 3 18 可编辑 WMAN AwirelessMAN orWMANawirelesscommunicationsnetworkthatcoversalargegeographicareasuchasacityorsuburb backhaulhasthegreatestshort termappeal 37 2020 3 18 可编辑 lastmilecouldestablishwirelessasanalternativetoresidentialbroadbandDSL cablemodem2to11GHzfrequencyrange 38 2020 3 18 可编辑 TwoWWANtechnologies includingGlobalSystemforMobileCommunications GSM andCodeDivisionMultipleAccess CDMA dominateWWANdeploymentsworldwide 39 2020 3 18 可编辑 Thesetwotechnologiesareexpectedtoevolveonparallelpathsfortheforeseeablefuture Wealsorecognizetheimportanceofindustrystandardstowidespreadadoption 40 2020 3 18 可编辑 InthesamewaythatearlycompetingWLANtechnologiesgavewaytotheIEEE801 11bstandard itisimportantthattheindustrydrivetowardworldwidestandardizationinotherwirelesstechnologies 41 2020 3 18 可编辑 1 Opticalfiber2 Opticalcommunicationsystems3 Advantagesofopticalfibercommunication TEXT5 3OpticalFiberCommunication 42 2020 3 18 可编辑 Terminology aperturen 孔径attenuationn 衰减dielectricwaveguide介质波导carbondioxidelaser二氧化碳激光器cleavevt 劈开cylindricaladj 圆柱状的electricarcn 电弧geometricoptics几何光学gradedindexfiber梯度型光纤 渐变型光纤 梯度折射率光纤heterojunctionn 异质结highnumericalaperture大数值孔径光纤 43 2020 3 18 可编辑 immuneadj 有免疫力的indicesn index的复数intersymbolinterference码间干扰micronn 微米monochromaticityn 单色性meridionalrayn 子午射线nanosecondn 纳秒neodymiumlaser钕激光器omnidirectionaladj 全方位的pickup获得parabolicadj 抛物线 44 2020 3 18 可编辑 silican 二氧化硅splicevt 拼接stepindexfiber阶跃光纤 阶跃折射率光纤sulphiden 硫化物transverseadj 横向的wavelengthdivisionmultiplexing分复用 45 2020 3 18 可编辑 Theopticalcommunicationsystemsaredifferentfrommicrowavecommunicationsystemsinmanyaspects Thecarrierfrequencyisabout100THzandthebitrateisabout1Tbit s 46 2020 3 18 可编辑 Spreadingofopticalbeamsisalwaysintheforwarddirectionduetotheshortwavelengths Suitableforfreespacecommunicationsabovetheearth satmospherelikeintersatellitecommunications 47 2020 3 18 可编辑 1 Opticalfiber Anopticalfiberisaglassorplasticfiberthatcarrieslightalongitslength Fiberopticsistheoverlapofappliedscienceandengineeringconcernedwiththedesignandapplicationofopticalfibers Fiberswhichsupportmanypropagationpathsortransversemodesarecalledmulti modefibers MMF 48 2020 3 18 可编辑 Fiberswhichcanonlysupportasinglemodearecalledsingle modefibers SMF Advantageslowattenuationtransmitsignalsoverawidebandwidth 49 2020 3 18 可编辑 ConstructionAnopticalfiberisacylindricaldielectricwaveguidethattransmitslightalongitsaxis bytheprocessoftotalinternalreflection Thefiberconsistsofacoresurroundedbyacladdinglayer 50 2020 3 18 可编辑 Fig 5 8Opticalfiberelectromagneticanalysis 51 2020 3 18 可编辑 2 Opticalcommunicationsystems 52 2020 3 18 可编辑 AlightsourceismadeofsemiconductorAtransferfunctionisrequiredtodefinethepowerlossassociatedwiththecouplingofthesignalpowerfromthelightsourcetothefibertransmissionline 53 2020 3 18 可编辑 FiberThelossinvolvedineitherjoiningthefiberbyapermanentspliceortheuseofademountableconnectorisatransferparametertobeincluded Fiber detectorjunctionPhotodetectorDesignalgorithm 54 2020 3 18 可编辑 3 Advantagesofopticalfibercommunication WiderbandwidthLowtransmissionlossDielectricwaveguideSignalsecuritySmallsizeandweight 55 2020 3 18 可编辑 EXERCISES 1 PleasetranslatethefollowingwordsandphrasesintoChinese 2 PleasetranslatethefollowingwordsandphrasesintoEnglish 4 Answerthefollowingquestionsaccordingtothetext 56 2020 3 18 可编辑 TEXT5 4BasicNetworkingConceptsforComputerNetwork 1 Introduction2 Networktopology3 Internetaddress4 Ports5 Datatransmission6 Protocols 57 2020 3 18 可编辑 Terminology ATMabbr AsynchronousTransferMode异步传输模式centralizevt 把 集中起来client servernetwork主从网 客服网converselyadv 相反地criterian 标准DNSabbr DomainNameSystem域名系统Encryptvt 加密 将 译成密码entityn 实体FDDIabbr FiberDistributedDataInterface光纤分布式数据接口ISDNabbr IntegratedServicesDigitalNetwork综合服务数字网leasedline租用线 专用线 58 2020 3 18 可编辑 memonicadj 记忆的 记忆术的peer to peernetwork对等网RFCabbr RequestForComments请求讲解 Internet标准 草案 semanticadj 语义的systematicadj 系统的 体系的subnetn 子网络syntaxn 语法 有秩序的排列tieredapplication分层应用userauthentication用户认证 59 2020 3 18 可编辑 1 Introduction Anetworkthatconnectscomputerslocatedwithinarelativelylimitedarea suchasanoffice abuildingoracampus isknownasaLocalAreaNetwork LAN Anetworkthatspansawidegeographicalarea usuallyacrosscities countriesorevencontinents isknownasWideAreaNetwork WAN 60 2020 3 18 可编辑 Theirmajordifferenceliesinhowdataandinformationisstored SeeTable5 7 61 2020 3 18 可编辑 ALANconsistsofnetworkedcomputers sometimescalledworkstationsandotherconnectingdevices AWANconsistsoftwoormoreLANsconnectedviaacommunicationchannelthatcombinestelephonelines leasedlines microwave orsatellites Itcancovercities countries andcontinents 62 2020 3 18 可编辑 Fig 5 12showsfourcommonconnectingdevices HubsRepeatersBridgesRouters 63 2020 3 18 可编辑 Fig 5 12Hardwarecomponentsofnetworking 64 2020 3 18 可编辑 2 Networktopology ThecommonnetworktopologiesareBus 65 2020 3 18 可编辑 StarRing 66 2020 3 18 可编辑 Usually morethanonetopologyisusedinanetwork Forexample inaschoolnetworksystem abus startopologyisusuallyusedwithahighbandwidthbusasthebackbone Thatbackboneconnectsanumberofstarnetworks Thestarnetworkisformedinacomputerroom EachworkstationisconnectedtothehubusingUTPcableandthebackboneisoftenanopticalfiber 67 2020 3 18 可编辑 ExamplesofLANtechnology EthernetFibberDistributedDataInterconnect FDDI 68 2020 3 18 可编辑 EthernetLAN AnEthernetLANisbasedonabustopologyandbroadcastcommunicationTokenring Ethernetisafamilyofframe basedcomputernetworkingtechnologiesforLANs astandardforconnectingcomputersintoaLANthenamecommonlyusedforIEEE802 3CSMA CD 69 2020 3 18 可编辑 FDDI FDDIspecifiesa100 Mbpstoken passing dual ringLANusingfiber opticcable CopperDistributedDataInterface CDDI hasemergedtoprovide100 Mbpsserviceovercopper 70 2020 3 18 可编辑 3 Internetaddress IPaddressesarenumericquantitiesthatareeasyforcomputerstoworkwith butnotforhumanstoremember Forexample 204 160 241 98 DomainNameSystem DNS serversareresponsiblefortranslatingmnemonictextualInternetaddressesintohardnumericInternetaddresses 71 2020 3 18 可编辑 EachorganizationthatmaintainsacomputernetworkwillhaveatleastoneserverhandlingDNSqueries Thatserver calledanameserver willholdalistofalltheIPaddresseswithinitsnetwork plusacacheofIPaddressesforrecentlyaccessedcomputersoutsidethenetwork Eachcomputeroneachnetworkneedstoknowthelocationofonlyonenameserver 72 2020 3 18 可编辑 WhenyourcomputerrequestsanIPaddress oneofthreethingshappens dependingonwhetherornottherequestedIPaddressiswithinyourlocalnetwork IftherequestedIPaddressisregisteredlocally thatis it swithinyourorganization snetwork you llreceivearesponsedirectlyfromoneofthelocalnameserverslistedinyourworkstationconfiguration Inthiscase thereusuallyislittleornowaitforaresponse 73 2020 3 18 可编辑 4 Ports AnIPportwillidentifyaspecificapplicationrunningonanInternethostmachine Aportisidentifiedbyanumber theportnumber Thenumberofportsisnotfunctionallylimited incontrasttoserialcommunicationswhereonly4portsareallowed 74 2020 3 18 可编辑 Therearesomeportnumberswhicharededicatedforspecific