電子與通信技術(shù)專業(yè)英語（第6版）課件 項目15 Wireless Fidelity

劉騁蔡靜主編電子與通信技術(shù)專業(yè)英語（第6版）高職高專電子信息類“十三五”規(guī)劃教材EnglishonElectronicandTelecommunicationTechnology03UnitⅢCommunicationTechnologyLesson15WirelessFidelityUnitⅢNewWordsfidelity [fi'del?ti] n. 逼真，保真度access ['?kses] vt. 使用，接近，獲取hassle ['h?sl] n. 麻煩事plug [pl?ɡ] v. 插上插頭disruption [dis'r?p?n] n. 破裂，毀壞，中斷console [k?n's?ul] n. 控制臺，操縱臺NewWordspropagation [,pr?p?'ɡei?n]n. 傳播，傳輸comprise [k?m'praiz]vt. 包含，包括，由……組成overlapping [,?uv?'l?pi?]adj. 重疊的router ['ru:t?]n. 路由器PhrasesandExpressionsDSSS(DirectSequenceSpreadSpectrum) 直接序列

擴(kuò)頻OFDM(OrthogonalFrequencyDivisionMultiplexing)正交頻分

復(fù)用FHSS(Frequency-HoppingSpreadSpectrum) 跳頻擴(kuò)頻PCI（PeripheralComponentInterconnect）

外設(shè)部件互

連標(biāo)準(zhǔn)PhrasesandExpressionsSSID(ServiceSetIDentifier) 服務(wù)集標(biāo)識符USB(UniversalSerialBus) 通用串行總線CardBus 具有總線控制功能的

32位PC卡PBCC(PacketBroadcastControlChannel) 分組廣播控制信道PhrasesandExpressionsminiPCI 內(nèi)置型無線網(wǎng)卡ExpressCard 擴(kuò)展接口Mbit/s(Megabitspersecond) 兆比特/秒WirelessFidelity，popularlyknownasWi-Fi,developedonIEEE802.11standards,iswidelyusedtechnologyadvancementinwirelesscommunication.

Asthenameindicates,WI-FIprovideswirelessaccesstoapplicationsanddataacrossaradionetwork.

WI-FIsetsupnumerouswaystobuildupaconnectionbetweenthetransmitterandthereceiversuchasDSSS,FHSS,IR–InfraredandOFDM.

Lesson15WirelessFidelityChineseTranslationofTexts無線相容性認(rèn)證，通常稱為Wi-Fi，它由IEEE802.11標(biāo)準(zhǔn)發(fā)展而來，是在無線通信中被廣泛應(yīng)用的先進(jìn)技術(shù)。顧名思義，WI-FI對無線網(wǎng)絡(luò)中的應(yīng)用程序和數(shù)據(jù)提供無線接入。WI-FI在發(fā)射端和接收端之間設(shè)置了許多方法來建立連接，如擴(kuò)頻，跳頻，紅外的連接和正交頻分復(fù)用。第15課

無線相容性認(rèn)證ChineseTranslationofTextsWi-FiprovidesitsuserswiththelibertyofconnectingtotheInternetfromanyplacesuchastheirhome,officeorapublicplacewithoutthehasslesofplugginginthewires.

Wi-Fiisquickerthantheconventionalmodemforaccessinginformationoveralargenetwork.Withthehelpofdifferentamplifiers,theuserscaneasilychangetheirlocationwithoutdisruptionintheirnetworkaccess.

Wi-Fidevicesarecompliantwitheachothertograntefficientaccessofinformationtotheuser.

ChineseTranslationofTexts

Wi-Fi讓用戶可以從任何地方如家中，辦公室或公共場所等自由連接到互聯(lián)網(wǎng)而不需要插上網(wǎng)線。訪問一個大型網(wǎng)絡(luò)的信息，Wi-Fi比傳統(tǒng)的調(diào)制解調(diào)器快。借助不同放大器的幫助，用戶可以很容易地改變自己的位置而不中斷其網(wǎng)絡(luò)接入。Wi-Fi設(shè)備相互兼容以給用戶有效的信息訪問。ChineseTranslationofTextsWi-FilocationwheretheuserscanconnecttothewirelessnetworkiscalledaWi-Fihotspot.Accessingawirelessnetworkthroughahotspotinsomecasesiscost-freewhileinsomeitmaycarryadditionalcharges.

ManystandardWi-FidevicessuchasPCI,miniPCI,USB,CardbusandPCcard,ExpressCardmaketheWi-Fiexperienceconvenientandpleasurablefortheusers.

ChineseTranslationofTexts用戶可以連接到無線網(wǎng)絡(luò)的地方被稱為Wi-Fi熱點。在某些情況下，通過熱點訪問無線網(wǎng)絡(luò)是免費的，而在另一些地方可能需要額外的費用。許多標(biāo)準(zhǔn)的Wi-Fi設(shè)備，如PCI，miniPCI，USB，Cardbus，以及PC卡，ExpressCard使得用戶的Wi-Fi體驗方便而愉快。ChineseTranslationofTextsWi-Fiusesradionetworkstotransmitdatabetweenitsnodes.

Suchnetworksaremadeupofcellsthatprovidecoverageacrossthenetwork.

Themorethenumberofcells,thegreaterandstrongeristhecoverageontheradionetwork.

ThemostpopularWi-Fitechnologysuchas802.11boperatesontherangeof2.40GHzupto2.4835GHzband.

ChineseTranslationofTexts

Wi-Fi使用無線網(wǎng)絡(luò)在節(jié)點之間傳輸數(shù)據(jù)。這種網(wǎng)絡(luò)是由覆蓋到整個網(wǎng)絡(luò)范圍的蜂窩組成。蜂窩的數(shù)量越多，無線網(wǎng)絡(luò)的覆蓋范圍越大、越強(qiáng)。最流行的Wi-Fi技術(shù)，例如802.11b，工作在2.40GHz到2.4835GHz頻段。ChineseTranslationofTextsThisprovidesacomprehensiveplatformforoperatingBluetoothstrategy,cellularphones,andotherscientificequipments.

While802.11atechnologyhastherangeof5.725GHzto5.850GHzandprovidesupto54Mbpsinspeed.

802.11gtechnologyisevenbetterasitcoversthreenon-overlappingchannels

andallowsPBCC.ChineseTranslationofTexts這為藍(lán)牙策略、手機(jī)和其他科學(xué)設(shè)備的工作提供了一個全面的平臺。雖然802.11a技術(shù)有著5.725GHz到5.850GHz的范圍，并可提供高達(dá)54Mbps（兆比特/秒）的速度，但802.11g技術(shù)甚至更好，它包括3個非重疊信道，并允許分組廣播控制信道。ChineseTranslationofTextsDevicethatcanuseWi-Fi(suchasapersonalcomputer,videogameconsole,Smartphone,tablet,ordigitalaudioplayer)canconnecttoanetworkresourcesuchastheInternetviaawirelessnetworkaccesspoint.Wi-Finetworkshavelimitedrange.ChineseTranslationofTexts可以使用無線網(wǎng)絡(luò)的設(shè)備（如個人電腦，游戲機(jī)，智能手機(jī)，平板電腦，或數(shù)字音頻播放器）都可以通過無線網(wǎng)絡(luò)接入點連接到英特網(wǎng)等網(wǎng)絡(luò)資源。Wi-Fi網(wǎng)絡(luò)范圍有限。ChineseTranslationofTextsAtypicalWi-Fihomerouterusing802.11bor802.11gmighthavearangeof45m(150ft)indoorsand90m(300ft)outdoors.Rangealsovaries,asWi-Fiisnoexceptiontothephysicsofradiowavepropagation,withfrequencyband.Wi-Fiinthe2.4GHzfrequencyblockhasbetterrangethanWi-Fiinthe5GHzfrequencyblock,andlessrangethantheoldestWi-Fi(andpre-Wi-Fi)900MHzblock.ChineseTranslationofTexts一個使用802.11b或802.11g的典型Wi-Fi家庭路由器可能有45米（150英尺）的室內(nèi)范圍和90米（300英尺）的戶外范圍。由于Wi-Fi毫無例外的是無線電波傳播，其范圍也會隨著頻段變化而變化。2.4GHz頻段的Wi-Fi的傳播范圍比5GHz頻段的更大，但小于早期900兆赫頻段的Wi-Fi。ChineseTranslationofTextsHotspotcoveragecancompriseanareaassmallasasingleroomwithwallsthatblockradiowavesoraslargeasmanysquaremiles—thisisachievedbyusingmultipleoverlappingaccesspoints（asshowninFig.15－1）.ChineseTranslationofTexts熱點覆蓋區(qū)域包括小到一個有阻止無線電波的墻的房間，大到幾平方英里——這是通過使用多個重疊的接入點實現(xiàn)的(如圖15－1所示)。ChineseTranslationofTextsNotesWirelessFidelity,popularlyknownasWi-Fi,developedonIEEE802.11standards,iswidelyusedtechnologyadvancementinwirelesscommunication.無線相容性認(rèn)證，通常稱為Wi-Fi，它由IEEE802.11標(biāo)準(zhǔn)發(fā)展而來，是在無線通信中被廣泛應(yīng)用的先進(jìn)技術(shù)。IEEE：InstituteOfElectricalandElectronicsEngineers.美國電氣與電子工程師協(xié)會。IEEE802.11standards：美國電氣與電子工程師協(xié)會標(biāo)準(zhǔn)。1NotesWi-FisetsupnumerouswaystobuildupaconnectionbetweenthetransmitterandthereceiversuchasDSSS,FHSS,IR–InfraredandOFDM.Wi-Fi在發(fā)射端和接收端之間設(shè)置了許多方法來建立連接，如擴(kuò)頻、跳頻、紅外的連接和正交頻分復(fù)用。IR-Infrared：IR是紅外線的意思，常用說法IR接口，也就是紅外線接口。2NotesManystandardWi-FidevicessuchasPCI,miniPCI,USB,CardbusandPCcard,ExpressCardmaketheWi-Fiexperienceconvenientandpleasurablefortheusers.許多標(biāo)準(zhǔn)的Wi-Fi設(shè)備，如PCI、miniPCI、USB、Cardbus及PC卡、ExpressCard，使得用戶的Wi-Fi體驗方便而愉快。3NotesManystandardWi-FidevicessuchasPCI,miniPCI,USB,CardbusandPCcard,ExpressCardmaketheWi-Fiexperienceconvenientandpleasurablefortheusers.PCI：PeripheralComponentInterconnect，一種由英特爾（Intel）公司1991年推出的用于定義局部總線的標(biāo)準(zhǔn)。PCcard：PC卡，一種用以給計算機(jī)及其他通信和電子設(shè)備添加諸如存儲器、大容量存儲器、網(wǎng)絡(luò)及無線通信等擴(kuò)展裝置的技術(shù)。3NotesManystandardWi-FidevicessuchasPCI,miniPCI,USB,CardbusandPCcard,ExpressCardmaketheWi-Fiexperienceconvenientandpleasurablefortheusers.miniPCI：miniPCI插槽也同樣是在PCI的基礎(chǔ)上發(fā)展起來的，miniPCI的定義與PCI基本上一致，只是在外形上進(jìn)行了微縮。ExpressCard：由PCMCIA聯(lián)盟推出的新規(guī)格，其優(yōu)點是體積更小，傳輸速度更快，更適合移動系統(tǒng)。3NotesManystandardWi-FidevicessuchasPCI,miniPCI,USB,CardbusandPCcard,ExpressCardmaketheWi-Fiexperienceconvenientandpleasurablefortheusers.USB：通用串行總線（UniversalSerialBus），是一新型界面規(guī)格，支持主系統(tǒng)與不同外設(shè)間的數(shù)據(jù)傳輸。USB允許外設(shè)在開機(jī)狀態(tài)下插拔使用，USB具有易于使用、高帶寬、可接多達(dá)127個外設(shè)、數(shù)據(jù)傳輸穩(wěn)定、支持即時聲音播放及影像壓縮等特點。目前在國內(nèi)市場可以見到的USB設(shè)備主要有掃描儀、數(shù)碼相機(jī)、打印機(jī)、集線器和外置存儲設(shè)備等。3NotesManystandardWi-FidevicessuchasPCI,miniPCI,USB,CardbusandPCcard,ExpressCardmaketheWi-Fiexperienceconvenientandpleasurablefortheusers.CardBus：PCMCIA推出的下一代高性能32位總線主控接口。它使現(xiàn)在只在桌面和較大的系統(tǒng)上才擁有的高級功能可以移入CardBus卡，從而可以用在移動環(huán)境下。3NotesWhile802.11atechnologyhastherangeof5.725GHzto5.850GHzandprovidesupto54Mbit/sinspeed.802.11gtechnologyisevenbetterasitcoversthreenon-overlappingchannelsandallowsPBCC.雖然802.11a技術(shù)有著5.725GHz到5.850GHz的范圍，并可提供高達(dá)54Mbit/s（兆比特/秒）的速度，但802.11g技術(shù)甚至更好，它包括3個非重疊信道，并允許分組廣播控制信道。4NotesWhile802.11atechnologyhastherangeof5.725GHzto5.850GHzandprovidesupto54Mbit/sinspeed.802.11gtechnologyisevenbetterasitcoversthreenon-overlappingchannelsandallowsPBCC.802.11atechnology：IEEE于1997年公告的無線區(qū)域網(wǎng)絡(luò)標(biāo)準(zhǔn)，適用于有線站臺與無線用戶或無線用戶之間的溝通聯(lián)結(jié)。802.11a是802.11的衍生版，于5.8GHz頻段提供了最高54Mbit/s的速率規(guī)格，并運用正交頻分復(fù)用編碼機(jī)制以取代802.11的FHSS或DSSS。802.11g在2.4GHz頻段上提供高于20Mbit/s的速率規(guī)格。4NotesAtypicalWi-Fihomerouterusing802.11bor802.11gmighthavearangeof45m(150ft)indoorsand90m(300ft)outdoors.一個使用802.11b或802.11g的典型Wi-Fi家庭路由器可能有45米（150英尺）的室內(nèi)范圍和90米（300英尺）的室外范圍。ft：英尺的意思，feet復(fù)數(shù)，foot單數(shù)，直接用縮寫ft即可。1ft=0.3048m（米）5Exercises1.WriteT(True)orF(False)besidethefollowingstatementsaboutthetext.a.Withthehelpofdifferentamplifiers,theuserscaneasilychangetheirlocationwithdisruptionintheirnetworkaccess.b.Wi-Fiusesradionetworkstotransmitdatabetweenitsnodes.c.Wi-Finetworksdon’thavelimitedrange.d.Wi-Fiinthe5GHzfrequencyblockhasbetterrangethanWi-Fiinthe2.4GHzfrequencyblock,andlessrangethantheoldestWi-Fi(andpre-Wi-Fi)900MHzblock.Exercises1.WriteT(True)orF(False)besidethefollowingstatementsaboutthetext.a.Withthehelpofdifferentamplifiers,theuserscaneasilychangetheirlocationwithdisruptionintheirnetworkaccess.b.Wi-Fiusesradionetworkstotransmitdatabetweenitsnodes.c.Wi-Finetworksdon’thavelimitedrange.d.Wi-Fiinthe5GHzfrequencyblockhasbetterrangethanWi-Fiinthe2.4GHzfrequencyblock,andlessrangethantheoldestWi-Fi(andpre-Wi-Fi)900MHzblock.F

T

FFExercises2.Fillinthemissingwordsaccordingtothetext.a.Wi-FiprovidesitsuserswiththelibertyofconnectingtotheInternetfrom

suchastheirhome,officeorapublicplacewithoutthe

inthewires.b.

cancompriseanareaassmallasasingleroomwithwallsthatblockradiowavesoraslargeasmanysquaremiles—thisisachievedby

.c.Wi-Filocationwheretheuserscanconnecttothewirelessnetworkiscalleda

.d.Themorenumberofcells,the

and

isthecoverageontheradionetwork.Exercises2.Fillinthemissingwordsaccordingtothetext.a.Wi-FiprovidesitsuserswiththelibertyofconnectingtotheInternetfrom anyplacesuchastheirhome,officeorapublicplacewithoutthehasslesofplugginginthewires.b.Hotspotcoveragecancompriseanareaassmallasasingleroomwithwallsthatblockradiowavesoraslargeasmanysquaremiles—thisisachievedbyusingmultipleoverlapping.c.Wi-FilocationwheretheuserscanconnecttothewirelessnetworkiscalledaWi-Fihotspot.d.Themorenumberofcells,thegreater