電子與通信技術(shù)專業(yè)英語(yǔ)UnitⅣ-17課件

UnitⅣCommunicationTechnologyLesson17OpticalFiberCommunicationsUnitⅣCommunicationTechnologNewWordsconvey[k?n'vei]vt.搬運(yùn),傳達(dá),轉(zhuǎn)讓transfer[tr?ns'f?:]n.移動(dòng),傳遞,轉(zhuǎn)移superimpose[,sju:p?rim'p?uz]v.添加,雙重microwave['maikr?uweiv]n.微波conversion[k?n'v?:??n]n.變換,轉(zhuǎn)化NewWordssemiconductor[,semik?n'd?kt?]n.半導(dǎo)體diode['dai?ud]n.二極管photodiode[,f?ut?u'dai?ud]n.光敏二極管,

光電二極管phototransistor[,f?ut?utr?n'zist?]n.光電晶體管,

光敏晶體管photoconductor[,f?ut?uk?n'd?kt?]n[物]

光電導(dǎo)體,光電導(dǎo)元件discrete[dis'kri:t]a.不連續(xù)的,離散的semiconductor[,semik?n'd?kt?]implement['implim?nt,'impliment]n.

工具,器具

vt.&v.貫徹,實(shí)現(xiàn),執(zhí)行encode[en'k?ud]vt.編碼equalizer['i:kw?laiz?]n.均衡器,平衡裝置decode[,di:'k?ud]vt.解碼,譯解implement['implim?nt,'impliPhrasesandExpressionsopticalfibern.光纖electromagneticwaven.電磁波avalanchephotodiode(APD)n.雪崩發(fā)光二極管front-endamplifiern.前置放大器PhrasesandExpressionsNotes1.…bysuperimposingormodulatingtheinformationontoanelectromagneticwavewhichactsasacarrierfortheinformationsignal.

⑴介詞by+動(dòng)名詞短語(yǔ)充當(dāng)狀語(yǔ)；

⑵which引導(dǎo)定語(yǔ)從句，修飾wave。Notes2.Thismodulatedcarrieristhentransmittedtotherequireddestinationwhereitisreceivedandtheoriginalinformationsignalisobtainedbydemodulation.

過(guò)去分詞短語(yǔ)required充當(dāng)定語(yǔ)，whereitis…bydemodulation是定語(yǔ)從句，兩者均修飾destination。2.Thismodulatedcarrieristh3.…byusingelectromagneticcarrierwavesoperatingatradiofrequenciesaswellasmicrowaveandmillimeterwavefrequencies.

⑴介詞by+動(dòng)名詞短語(yǔ)充當(dāng)狀語(yǔ)；

⑵aswellas意思是“以及”，相當(dāng)于and，常用于句中，下文中仍有這種用法。再如：HecanspeakEnglishaswellasChinese。請(qǐng)比較：HecanspeakEnglish,andhecanspeakChineseaswell(aswell用于句末，相當(dāng)于too)。3.…byusingelectromagneticca4.However,“communication”mayalsobeachievedbyusinganelectromagneticcarrierwhichisselectedfromtheopticalrangeoffrequencies.

Which引導(dǎo)定語(yǔ)從句，修electromagneticcarrier。4.However,“communication”maya5.Inthiscasetheinformationsourceprovidesanelectricalsignaltoatransmittercomprisinganelectricalstagewhichdrivesanopticalsourcetogivemodulationofthelightwavecarrier.

⑴inthiscase：“在這種場(chǎng)合下，既然這樣”；⑵which引導(dǎo)定語(yǔ)從句。5.Inthiscasetheinformation6.…toprovidegainaswellaslinearsignalprocessingandnoisebandwidthreduction.

此為不定式短語(yǔ)，充當(dāng)目的狀語(yǔ)。6.…toprovidegainaswellasTranslationofTextsLesson17OpticalFiberCommunicationsCommunicationmaybebroadlydefinedasthetransferofinformationfromonepointtoanother.Whentheinformationistobeconveyedoveranydistanceacommunicationsystemisusuallyrequired.Withinacommunicationsystemtheinformationtransferisfrequentlyachievedbysuperimposingormodulatingtheinformationontoanelectromagneticwavewhichactsasacarrierfortheinformationsignal.TranslationofTextsLesson17第17課光纖通信廣義地說(shuō)，把信息從一點(diǎn)傳送到另一點(diǎn)就稱為通信。當(dāng)信息跨越一段距離被傳送時(shí)，就需要一個(gè)通信系統(tǒng)。在通信系統(tǒng)中，信息傳送是通過(guò)把信息疊加在電磁波上或?qū)﹄姶挪ㄟM(jìn)行調(diào)制來(lái)實(shí)現(xiàn)的，電磁波起著載送信號(hào)的作用。第17課光纖通信Thismodulatedcarrieristhentransmittedtotherequireddestinationwhereitisreceivedandtheoriginalinformationsignalisobtainedbydemodulation.Sophisticatedtechniqueshavebeendevelopedforthisprocessbyusingelectromagneticcarrierwavesoperatingatradiofrequenciesaswellasmicrowaveandmillimeterwavefrequencies.However,“communication”mayalsobeachievedbyusinganelectromagneticcarrierwhichisselectedfromtheopticalrangeoffrequencies.Thismodulatedcarrieris

這一經(jīng)過(guò)調(diào)制的載波隨后被傳送到要求到達(dá)的目的地，在那里被接收，并且通過(guò)解調(diào)還原成原始信息。在運(yùn)用電磁載波的領(lǐng)域，高新技術(shù)得到進(jìn)一步的發(fā)展，比如射頻、微波以及毫米波的頻率都被用來(lái)作為載波頻率。在通信中，也可選擇光波的頻率作為載波頻率。這一經(jīng)過(guò)調(diào)制的載波隨后被傳送到要求到達(dá)的目的地，在那里TypicalopticalfibercommunicationssystemisshowninFig.20-1.Inthiscasetheinformationsourceprovidesanelectricalsignaltoatransmittercomprisinganelectricalstagewhichdrivesanopticalsourcetogivemodulationofthelightwavecarrier.Theopticalsourcewhichprovidestheelectrical-opticalconversionmaybeeitherasemiconductorlaserorlightemittingdiode(LED).Typicalopticalfibe

典型的光纖通信系統(tǒng)如圖17－1所示。信源提供電信號(hào)給發(fā)射機(jī)，發(fā)射機(jī)組成一個(gè)電子平臺(tái)來(lái)驅(qū)動(dòng)光源以完成對(duì)光載波的調(diào)制。光源是由發(fā)光二極管或半導(dǎo)體激光管構(gòu)成的，它完成光—電變換。傳輸媒介由光纖（纜）組成。典型的光纖通信系統(tǒng)如圖17－1所示。信源

Thetransmissionmediumconsistsofanopticalfibercableandthereceiverconsistsofanopticaldetectorwhichdrivesafurtherelectricalstageandhenceprovidesdemodulationoftheopticalcarrier.Photodiodes(p-n,p-i-noravalanche)and,insomeinstances,phototransistorandphotoconductorsareutilizedforthedetectionoftheopticalsignalandtheoptical-electricalconversion.Thusthereisarequirementforelectricalinterfacingateitherendoftheopticallinkandatpresentthesignalprocessingisusuallyperformedelectrically.Thetransmissionmediumco

光接收機(jī)由驅(qū)動(dòng)后面電路平臺(tái)的光探測(cè)器構(gòu)成，用以完成對(duì)已調(diào)光載波的解調(diào)。用于檢測(cè)光信號(hào)和進(jìn)行光—電轉(zhuǎn)換的器件有：光電二極管（P-N、P-I-N或雪崩管）、發(fā)光三極管以及光敏電阻等。因此，在光系統(tǒng)鏈路的兩端都要求有電接口，并且在現(xiàn)階段，信號(hào)處理通常是通過(guò)電路實(shí)現(xiàn)的。光接收機(jī)由驅(qū)動(dòng)后面電路平臺(tái)的光探測(cè)器構(gòu)成，用以完成對(duì)已Theopticalcarriermaybemodulatedbyusingeitherananalogordigitalinformationsignal.Analogmodulationinvolvesthevariationofthelightemittedfromtheopticalsourceinacontinuousmanner.Withdigitalmodulation,however,discretechangesinthelightintensityareobtained(i.e.on-offpulses).Theopticalcarrier

模擬或數(shù)字的信號(hào)均可用來(lái)調(diào)制光載波。模擬調(diào)制是指從光源處發(fā)射的連續(xù)光強(qiáng)度的變化，而數(shù)字調(diào)制則不然，它是通過(guò)光強(qiáng)度離散的變化（比如，有無(wú)光脈沖）來(lái)實(shí)現(xiàn)的。模擬或數(shù)字的信號(hào)均可用來(lái)調(diào)制光載波。模擬Althoughoftensimplertoimplement,analogmodulationwithanopticalfibercommunicationsystemislessefficient,requiringafarhighersignaltonoiseratioatthereceiverthandigitalmodulation.Also,thelinearityneededforanalogmodulationisnotalwaysprovidedbysemiconductoropticalsource,especiallyathighmodulationfrequencies.Forthesereasons,analogopticalfibercommunicationlinkaregenerallylimitedtoshorterdistancesandlowerbandwidthsthandigitallinks.Althoughoftensimplerto

雖然簡(jiǎn)單易行，但模擬調(diào)制在光通信系統(tǒng)調(diào)制中調(diào)制效率較低，而且與數(shù)字調(diào)制相比，需要高得多的信噪比。模擬調(diào)制所必需的線性不總是來(lái)源于半導(dǎo)體光源，尤其是在高頻調(diào)制中。基于上述原因，與數(shù)字光通信系統(tǒng)相比較，模擬光通信鏈路通常被限制使用在更短的通信距離和更窄的帶寬上。雖然簡(jiǎn)單易行，但模擬調(diào)制在光通信系統(tǒng)調(diào)制中調(diào)制效率較低

Initially,theinputdigitalsignalfromtheinformationsourceissuitablyencodedforopticaltransmission.Thelaserdrivecircuitdirectlymodulatestheintensityofthesemiconductorlaserwiththeencodeddigitalsignal.Henceadigitalopticalsignalislaunchedintotheopticalfibercable.Theavalanchephotodiode(APD)detectorisfollowedbyafront-endamplifierandequalizerorfiltertoprovidegainaswellaslinearsignalprocessingandnoisebandwidthreduction.Finally,thesignalobtainedisdecodedtogivetheoriginaldigitalinformation.Initially,theinpu

首先，輸入的信源數(shù)字信號(hào)被適當(dāng)?shù)鼐幋a以進(jìn)行光傳輸。激光器的驅(qū)動(dòng)電路通過(guò)這些已編碼的數(shù)字信號(hào)來(lái)直接調(diào)制激光器的發(fā)光強(qiáng)度，然后數(shù)字光信號(hào)被注入光纖電纜。在接收端，信號(hào)通過(guò)雪崩發(fā)光二極管（APD）后進(jìn)入前置放大器和均衡器或?yàn)V波器，放大器用來(lái)提供增益、濾波器用來(lái)對(duì)信號(hào)進(jìn)行線性處理和減少噪聲帶寬。最后，信號(hào)通過(guò)解碼得到原始數(shù)字信號(hào)。首先，輸入的信源數(shù)字信號(hào)被適當(dāng)?shù)鼐幋a以進(jìn)Exercises1.WriteT(True)orF(False)besidethefollowingstatementsaboutthetext.Exercisesa.Thismodulatedcarrieristhentransmittedtotherequireddestinationwhereitisreceivedandtheoriginalinformationsignalisobtainedbymodulation.b.Sophisticatedtechniqueshavebeendevelopedforthisprocessbyusingmagneticcarrierwavesoperatingatradiofrequenciesaswellasmicrowaveandmillimeterwavefrequenciesa.Thismodulatedcarrieristc.Theinformationsourceprovidesanelectricalsignaltoatransmittercomprisinganelectricalstagewhichdrivesanopticalsourcetogivemodulationofthelightwavecarrier.d.Thetransmissionmediumconsistsofanopticalfibercableandthereceiverc.Theinformationsourceprovie.Theopticalcarrierismodulatedbyusingneitherananalognordigitalinformationsignal.f.Withdigitalmodulation,discretechangesinthelightintensityarenotobtained.e.Theopticalcarrierismodug.Analogmodulationwithanopticalfibercommunicationsystemismoreefficient,requiringafarlowersignaltonoiseratioatthereceiverthandigitalmodulation.h.Theinputdigitalsignalfromtheinformationsourceisnotsuitablyencodedforopticaltransmission.g.Analogmodulationwithano2.Fillinthemissingwordsaccordingtothetext.2.Fillinthemissingwordsa.Withinacommunicationsystemtheinformationtransferis___________bysuperimposingormodulatingtheinformationontoanelectromagneticwavewhichactsasacarrier.a.Withinacommunicationsystb.Photodiodes(p-n,p-i-noravalanche)and_______________and_____________areutilizedforthedetectionoftheopticalsignalandtheoptical-electricalconversion.b.Photodiodes(p-n,p-i-norc.Thelaserdrivecircuitdirectlymodulatestheintensityofthesemiconductorlaserwiththeencodeddigitalsignal.Hencea____________________islaunchedintotheopticalfibercable.c.Thelaserdrivecircuitdird.Thereisarequirementforelectricalinterfacingateitherendoftheopticallinkandatpresentthe___________________isusuallyperformedelectrically.d.Thereisarequirementfor3.TranslatethethirdparagraphintoChinese.

3.TranslatethethirdparagraEndEndUnitⅣCommunicationTechnologyLesson17OpticalFiberCommunicationsUnitⅣCommunicationTechnologNewWordsconvey[k?n'vei]vt.搬運(yùn),傳達(dá),轉(zhuǎn)讓transfer[tr?ns'f?:]n.移動(dòng),傳遞,轉(zhuǎn)移superimpose[,sju:p?rim'p?uz]v.添加,雙重microwave['maikr?uweiv]n.微波conversion[k?n'v?:??n]n.變換,轉(zhuǎn)化NewWordssemiconductor[,semik?n'd?kt?]n.半導(dǎo)體diode['dai?ud]n.二極管photodiode[,f?ut?u'dai?ud]n.光敏二極管,

光電二極管phototransistor[,f?ut?utr?n'zist?]n.光電晶體管,

光敏晶體管photoconductor[,f?ut?uk?n'd?kt?]n[物]

光電導(dǎo)體,光電導(dǎo)元件discrete[dis'kri:t]a.不連續(xù)的,離散的semiconductor[,semik?n'd?kt?]implement['implim?nt,'impliment]n.

工具,器具

vt.&v.貫徹,實(shí)現(xiàn),執(zhí)行encode[en'k?ud]vt.編碼equalizer['i:kw?laiz?]n.均衡器,平衡裝置decode[,di:'k?ud]vt.解碼,譯解implement['implim?nt,'impliPhrasesandExpressionsopticalfibern.光纖electromagneticwaven.電磁波avalanchephotodiode(APD)n.雪崩發(fā)光二極管front-endamplifiern.前置放大器PhrasesandExpressionsNotes1.…bysuperimposingormodulatingtheinformationontoanelectromagneticwavewhichactsasacarrierfortheinformationsignal.

⑴介詞by+動(dòng)名詞短語(yǔ)充當(dāng)狀語(yǔ)；

⑵which引導(dǎo)定語(yǔ)從句，修飾wave。Notes2.Thismodulatedcarrieristhentransmittedtotherequireddestinationwhereitisreceivedandtheoriginalinformationsignalisobtainedbydemodulation.

過(guò)去分詞短語(yǔ)required充當(dāng)定語(yǔ)，whereitis…bydemodulation是定語(yǔ)從句，兩者均修飾destination。2.Thismodulatedcarrieristh3.…byusingelectromagneticcarrierwavesoperatingatradiofrequenciesaswellasmicrowaveandmillimeterwavefrequencies.

⑴介詞by+動(dòng)名詞短語(yǔ)充當(dāng)狀語(yǔ)；

⑵aswellas意思是“以及”，相當(dāng)于and，常用于句中，下文中仍有這種用法。再如：HecanspeakEnglishaswellasChinese。請(qǐng)比較：HecanspeakEnglish,andhecanspeakChineseaswell(aswell用于句末，相當(dāng)于too)。3.…byusingelectromagneticca4.However,“communication”mayalsobeachievedbyusinganelectromagneticcarrierwhichisselectedfromtheopticalrangeoffrequencies.

Which引導(dǎo)定語(yǔ)從句，修electromagneticcarrier。4.However,“communication”maya5.Inthiscasetheinformationsourceprovidesanelectricalsignaltoatransmittercomprisinganelectricalstagewhichdrivesanopticalsourcetogivemodulationofthelightwavecarrier.

⑴inthiscase：“在這種場(chǎng)合下，既然這樣”；⑵which引導(dǎo)定語(yǔ)從句。5.Inthiscasetheinformation6.…toprovidegainaswellaslinearsignalprocessingandnoisebandwidthreduction.

此為不定式短語(yǔ)，充當(dāng)目的狀語(yǔ)。6.…toprovidegainaswellasTranslationofTextsLesson17OpticalFiberCommunicationsCommunicationmaybebroadlydefinedasthetransferofinformationfromonepointtoanother.Whentheinformationistobeconveyedoveranydistanceacommunicationsystemisusuallyrequired.Withinacommunicationsystemtheinformationtransferisfrequentlyachievedbysuperimposingormodulatingtheinformationontoanelectromagneticwavewhichactsasacarrierfortheinformationsignal.TranslationofTextsLesson17第17課光纖通信廣義地說(shuō)，把信息從一點(diǎn)傳送到另一點(diǎn)就稱為通信。當(dāng)信息跨越一段距離被傳送時(shí)，就需要一個(gè)通信系統(tǒng)。在通信系統(tǒng)中，信息傳送是通過(guò)把信息疊加在電磁波上或?qū)﹄姶挪ㄟM(jìn)行調(diào)制來(lái)實(shí)現(xiàn)的，電磁波起著載送信號(hào)的作用。第17課光纖通信Thismodulatedcarrieristhentransmittedtotherequireddestinationwhereitisreceivedandtheoriginalinformationsignalisobtainedbydemodulation.Sophisticatedtechniqueshavebeendevelopedforthisprocessbyusingelectromagneticcarrierwavesoperatingatradiofrequenciesaswellasmicrowaveandmillimeterwavefrequencies.However,“communication”mayalsobeachievedbyusinganelectromagneticcarrierwhichisselectedfromtheopticalrangeoffrequencies.Thismodulatedcarrieris

這一經(jīng)過(guò)調(diào)制的載波隨后被傳送到要求到達(dá)的目的地，在那里被接收，并且通過(guò)解調(diào)還原成原始信息。在運(yùn)用電磁載波的領(lǐng)域，高新技術(shù)得到進(jìn)一步的發(fā)展，比如射頻、微波以及毫米波的頻率都被用來(lái)作為載波頻率。在通信中，也可選擇光波的頻率作為載波頻率。這一經(jīng)過(guò)調(diào)制的載波隨后被傳送到要求到達(dá)的目的地，在那里TypicalopticalfibercommunicationssystemisshowninFig.20-1.Inthiscasetheinformationsourceprovidesanelectricalsignaltoatransmittercomprisinganelectricalstagewhichdrivesanopticalsourcetogivemodulationofthelightwavecarrier.Theopticalsourcewhichprovidestheelectrical-opticalconversionmaybeeitherasemiconductorlaserorlightemittingdiode(LED).Typicalopticalfibe

典型的光纖通信系統(tǒng)如圖17－1所示。信源提供電信號(hào)給發(fā)射機(jī)，發(fā)射機(jī)組成一個(gè)電子平臺(tái)來(lái)驅(qū)動(dòng)光源以完成對(duì)光載波的調(diào)制。光源是由發(fā)光二極管或半導(dǎo)體激光管構(gòu)成的，它完成光—電變換。傳輸媒介由光纖（纜）組成。典型的光纖通信系統(tǒng)如圖17－1所示。信源

Thetransmissionmediumconsistsofanopticalfibercableandthereceiverconsistsofanopticaldetectorwhichdrivesafurtherelectricalstageandhenceprovidesdemodulationoftheopticalcarrier.Photodiodes(p-n,p-i-noravalanche)and,insomeinstances,phototransistorandphotoconductorsareutilizedforthedetectionoftheopticalsignalandtheoptical-electricalconversion.Thusthereisarequirementforelectricalinterfacingateitherendoftheopticallinkandatpresentthesignalprocessingisusuallyperformedelectrically.Thetransmissionmediumco

光接收機(jī)由驅(qū)動(dòng)后面電路平臺(tái)的光探測(cè)器構(gòu)成，用以完成對(duì)已調(diào)光載波的解調(diào)。用于檢測(cè)光信號(hào)和進(jìn)行光—電轉(zhuǎn)換的器件有：光電二極管（P-N、P-I-N或雪崩管）、發(fā)光三極管以及光敏電阻等。因此，在光系統(tǒng)鏈路的兩端都要求有電接口，并且在現(xiàn)階段，信號(hào)處理通常是通過(guò)電路實(shí)現(xiàn)的。光接收機(jī)由驅(qū)動(dòng)后面電路平臺(tái)的光探測(cè)器構(gòu)成，用以完成對(duì)已Theopticalcarriermaybemodulatedbyusingeitherananalogordigitalinformationsignal.Analogmodulationinvolvesthevariationofthelightemittedfromtheopticalsourceinacontinuousmanner.Withdigitalmodulation,however,discretechangesinthelightintensityareobtained(i.e.on-offpulses).Theopticalcarrier

模擬或數(shù)字的信號(hào)均可用來(lái)調(diào)制光載波。模擬調(diào)制是指從光源處發(fā)射的連續(xù)光強(qiáng)度的變化，而數(shù)字調(diào)制則不然，它是通過(guò)光強(qiáng)度離散的變化（比如，有無(wú)光脈沖）來(lái)實(shí)現(xiàn)的。模擬或數(shù)字的信號(hào)均可用來(lái)調(diào)制光載波。模擬Althoughoftensimplertoimplement,analogmodulationwithanopticalfibercommunicationsystemislessefficient,requiringafarhighersignaltonoiseratioatthereceiverthandigitalmodulation.Also,thelinearityneededforanalogmodulationisnotalwaysprovidedbysemiconductoropticalsource,especiallyathighmodulationfrequencies.Forthesereasons,analogopticalfibercommunicationlinkaregenerallylimitedtoshorterdistancesandlowerbandwidthsthandigitallinks.Althoughoftensimplerto

雖然簡(jiǎn)單易行，但模擬調(diào)制在光通信系統(tǒng)調(diào)制中調(diào)制效率較低，而且與數(shù)字調(diào)制相比，需要高得多的信噪比。模擬調(diào)制所必需的線性不總是來(lái)源于半導(dǎo)體光源，尤其是在高頻調(diào)制中?；谏鲜鲈?，與數(shù)字光通信系統(tǒng)相比較，模擬光通信鏈路通常被限制使用在更短的通信距離和更窄的帶寬上。雖然簡(jiǎn)單易行，但模擬調(diào)制在光通信系統(tǒng)調(diào)制中調(diào)制效率較低

Initially,theinputdigitalsignalfromtheinformationsourceissuitablyencodedforopticaltransmission.Thelaserdrivecircuitdirectlymodulatestheintensityofthesemiconductorlaserwiththeencodeddigitalsignal.Henceadigitalopticalsignalislaunchedintotheopticalfibercable.Theavalanchephotodiode(APD)detectorisfollowedbyafront-endamplifierandequalizerorfiltertoprovidegainaswellaslinearsignalprocessingandnoisebandwidthreduction.Finally,thesignalobtainedisdecodedtogivetheoriginaldigitalinformation.Initially,theinpu

首先，輸入的信源數(shù)字信號(hào)被適當(dāng)?shù)鼐幋a以進(jìn)行光傳輸。激光器的驅(qū)動(dòng)電路通過(guò)這些已編碼的數(shù)字信號(hào)來(lái)直接調(diào)制激光器的發(fā)光強(qiáng)度，然后數(shù)字光信號(hào)被注入光纖電纜。在接收端，信號(hào)通過(guò)雪崩發(fā)光二極管（APD）后進(jìn)入前置放大器和均衡器或?yàn)V波器，放大器用來(lái)提供增益、濾波器用來(lái)對(duì)信號(hào)進(jìn)行線性處理和減少噪聲帶寬。最后，信號(hào)通過(guò)解碼得到原始數(shù)字信號(hào)。首先，輸入的信源數(shù)字信號(hào)被適當(dāng)?shù)鼐幋a以進(jìn)Exercises1.WriteT(True)orF(False)besidethefollowingstatementsaboutthetext.Exercisesa.Thismodulatedcarrieristhentransmittedtotherequireddestinationwhereitisreceivedandtheoriginalinformationsignalisobtainedbymodulation.b.Sophisticatedtechniqueshavebeendevelopedforthisprocessbyu