新视野大学英语第四册第四单元课件

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1、TheTelecommunicationsRevolutionBook4,Unit4TextA2Propernamestelecommunicationsopticalfiber(L.6)/high-capacityopticalfiberlinks(L.38)cable(L.7)copperwire(L.8)digitalswitches(L.8)/digitalmodel(L.22)/digitalmobilephonesystems(L.51)wirelesstransmissionsystems(L.9)the

2、InformationAge(L.10)aspider’swebofdigitalandwirelesscommunicationlinks(L.11)电信光纤.光学纤维/高容量的光纤电缆网电缆铜线（电缆）数字转换器/数字模式/数字移动电话系统无线传播系统信息时代一个蜘蛛网般的数字和无线通信网络3Propernamestheinformationsuperhighway(L.39)logon(to)/logout/off(L.40)theelectronicdata(L.42)/electron(L.73)paperl

3、esstrading(L.43)radiotower(L.53)stringlinesacrossmountainridges(L.53)wirelesscall(L.55)fixedlines(L.56)信息高速公路进入（计算机）系统；登录/退出电子数据/电子（信号）无纸化交易无线电发射塔翻山越岭架设线路无线电话固定线路4telephone&mobilephoneInternetandemailfaxradiodigitalTVsatelliteTelecommunicationsWhattelecommunicat

4、ionsdevicesareavailableinyourlife?Whatdoestelecommeantoyou?5TelecommunicationsTelecommunications,fromGreek,means“communicationsatadistance”.Thefirsttrend:theincredibleincreaseintheprocessingpowerofdigitalcomputers,namely,dramaticdecreasesinphysicalsize,dramatici

5、ncreasesincomplexity,speedandcapacity.Thesecondtrend:theexplosivegrowthintransmissioncapacitythroughthewidespreaduseofopticalfiberacrosscontinentsandunderoceans.6opticalfiberOpticalfiber(or“fiberoptic”)oftenreferstothemediumandthetechnologyassociatedwiththetrans

6、missionofinformationaslightpulses(光脉冲)alongaglassorplasticwireorfiber.Opticalfibercarriesmuchmoreinformationthanconventionalcopperwireandisingeneralnotsubjecttoelectromagnetic电磁的interferenceandtheneedtoretransmitsignals.Mosttelephonecompanylong-distancelinesaren

7、owofopticalfiber.7InformationAgeWhenwesaythatweliveintheinformationage,wemeanthat weliveinatimewheninformationisveryimportantandeasytoget.Theinformationageisaneraoffundamentalandglobalchangeinintellectual,philosophical,culturalandsocialterms.Today’sinformationag

8、ebeganwiththetelegraph.Itwasthefirstinstrumenttotransforminformationintoelectricalformandtransmititreliablyoverlongdistances.Newtechniquesofencodinganddistributingdig