專業(yè)英語王立琦版課文翻譯

ResistorAresistorisatwo-terminalelectroniccomponentthatopposesanelectriccurrentbyproducingavoltagedropbetweenitsterminalsinproportiontothecurrent,thatis,inaccordancewithOhm’slaw:V=IR.TheelectresistanceRisequaltothevoltagedropVacrosstheresistordividedbythecurrentIthroughtheresistor.Resistorsareusedaspartofelectricalnetworksandelectroniccircuits.譯：電阻器是一個(gè)二端口電子元件

,電阻是阻擋電流流動(dòng)，經(jīng)過按比率產(chǎn)生其端子之間的電壓降的電流

,也就是說

,依據(jù)歐姆定律:V=IR

。電阻

R等于電壓降

V除以經(jīng)過電阻的電流

I。電阻作為電子網(wǎng)絡(luò)和電子電路的一部分。TransistorInelectronics,atransistorisasemiconductordevicecommonlyusedtoamplifyorswitchelectronicsignals.Atransistorismadeofasolidpieceofasemiconductormaterial,withatleastthreeterminalsforconnectiontoanexternalcircuit.Avoltageorcurrentappliedtoonepairofthetransistor’sterminalschangesthecurrentfthroughanotherpairofterminals.Becausethecontrolledcurrentcanbemuchlargerthanthecontrollingcurrent,thetransistorprovidesamplificationofasignal.Thetransistoristhefundamentalbuildingblockofmodernelectronicdevices,andisusedinradio,telephone,computerandotherelectronicsystems.Sometransistorsarepackagedindividuallybutmostarefoundinintegratedcircuits.譯：在電子技術(shù)中，晶體管是一種，常用來放大或進(jìn)行開關(guān)控制電子信號(hào)的半導(dǎo)體器。晶體管是由一塊固體半導(dǎo)體資料制成的，且起碼有三個(gè)終端與外面電路連結(jié)。電壓或電流合用于一雙晶體管的終端改變當(dāng)前流經(jīng)的另一對(duì)終端。因?yàn)槭芸仉娏髂軌蜻h(yuǎn)大于控制電流，晶體管供給信號(hào)的放大。晶體管是建立現(xiàn)代電子設(shè)施的基本單元，并在收音機(jī)，電話，計(jì)算機(jī)和其余電子系統(tǒng)被使用。一些晶體管被獨(dú)自包裝，但大部分都在集成電路中。TransformerAtransformerisadevicethattransferselectricalenergyfromonecircuittoantherthroughinductivelycoupledelectricalconductors.Achangingcurrentinthefirstcircuitcreatesachangingmagneticfield;inturn,thismagneticfieldinducesachangingvoltageinthesecondcircuit.Byaddingaloadtothesecondarycircuit,onecanmakecurrentflowinthetransformer,thustransferringenergyfromonecircuittotheother.譯：變壓器是一種經(jīng)過感覺耦合將電能從一個(gè)電路傳輸?shù)搅硪粋€(gè)電路的裝置。在第一電路中的一個(gè)變化的電流創(chuàng)立一個(gè)不停變化的磁場(chǎng)；反過來，這個(gè)磁場(chǎng)引誘第二個(gè)電路中的電壓變化。經(jīng)過向二次回路中增添負(fù)載，使電流在變壓器中流動(dòng)，進(jìn)而將能量從一個(gè)電路傳達(dá)到另一個(gè)電路中。RelayArelayisanelectricalswitchthatopensandclosesunderthecontrolofanotherelectricalcircuit.Intheoriginalform,theswitchisoperatedbyanelectromagnettoopenorcloseoneormanysetsofcontacts.ItwasinventedbyJosephHenryin1835.Becausearelayisabletocontrolanoutputcircuitofhigherpowerthantheinputcircuit,itcanbeconsideredtobe,inabroadsense,aformofanelectricalamplifier.譯：繼電器是一種電子開關(guān),控制另一個(gè)電路的翻開和封閉。在原始形式中，該開關(guān)是由一個(gè)電磁鐵操作，翻開或封閉一個(gè)或多個(gè)觸點(diǎn)。它是由約瑟夫亨利在1835年發(fā)明的。因?yàn)槔^電器能夠控制比輸入電路功率更高的輸出電路，廣義上說,它能夠被以為是電子放大器的一種形式。TypesofcircuitsInanycircuitwheretheonlyoppositiontotheflowofelectronsisresistance,thereisadefiniterelationshipbetween’slaw.譯：任何電路中電阻只是阻擋電子的流動(dòng),電壓，電流和電阻的值之間有一個(gè)明確關(guān)系。這類關(guān)系在1827年由格奧爾格·西蒙·歐姆發(fā)現(xiàn)。它被稱為歐姆定律。DualityBecauseofthestrongsimilaritybetweentheFourieranalysisandsynthesisequationsincontinuoustime,thereisadualitybetweenthetimedomainandfrequencydomain.However,forthediscrete-timeFouriertransformsofaperiodicsignals,nosimilardualityexists,sinceaperiodicsignalsandtheirFouriertransformsareverydifferentkindsoffunctions:Aperiodicdiscrete-timesignalsare,ofcourse,aperiodicsequences,whiletheirFouriertransformsarealwaysperiodicfunctionsofacontinuousfrequencyvariable.譯：因?yàn)楦道锶~剖析和合成方程在在連續(xù)時(shí)間上有很大的相像性

,有一個(gè)時(shí)域和頻域之間的二元性。但是

,關(guān)于非周期信號(hào)的失散傅里葉變換能:自然,非周期失散時(shí)間信號(hào)

,沒有近似的二元性存在,因?yàn)榉侵芷谛盘?hào)和它們的傅立葉變換有著截然不一樣的功,非周期序列,但是他們的傅里葉變換老是周期性的頻次連續(xù)變化的函數(shù)。NetworkConfigurationBroadlyspeaking,therearetwotypesofnetworkconfigurationbasedontheirlayout,peer-to-peernetworksandclient/servernetwork.Peer-to-peernetworksaremorecommonlyimplementedwherelessthantencomputersareinvolvedandwherestrictsecurityisnotnecessary.Allcomputershavethesamestatus,hencetheterm”peer”,andtheycommunwitheachotheronanequalfooting.Files,suchaswordprocessingorspreadsheetdocuments,canbesharedacrossthenetworkandallthecomputersonthenetworkcansharedevices,suchasprintersorscanners,whichareconnectedtoanyonecomputer.譯：廣義地說，有鑒于兩種種類網(wǎng)絡(luò)配置的的布局，平等網(wǎng)絡(luò)和客戶機(jī)/服務(wù)器網(wǎng)絡(luò)。平等網(wǎng)絡(luò)較為廣泛實(shí)現(xiàn)，此中不到10臺(tái)計(jì)算機(jī)參加并且不需要很嚴(yán)格的安全性。全部計(jì)算機(jī)都擁有相同的地位，所以被稱為“平等”，并且他們平分秋色互相通訊。文件，比如文字辦理或電子表格文檔，能夠經(jīng)過網(wǎng)絡(luò)共享來和全部的網(wǎng)絡(luò)上的計(jì)算機(jī)進(jìn)行設(shè)施共享，打印機(jī)或許掃描儀，能夠連結(jié)就任何一臺(tái)計(jì)算機(jī)。SignalsAsignal,asthetermimplies,isasetofinformationordata.Examplesincludeatelephoneoratelevisionsignal,monthlysalesofacorporation,orthedailyclosingpricesofastockmarket.Inalltheseexamples,thesignalsarefunctionsoftheindependentvariabletime.Thisisnotalwaysthecase,however,whenanelectricalchargeisdistributedoverabody,forinstance,thesignalisthechargedensity,afunctionofspaceratherthantime.Inthisbookwedealalmostexclusivelywithsignalsthatarefunctionsoftime.Thediscussion,however,appliesequallywelltootherindependentvariables.譯：信號(hào)，正如這個(gè)術(shù)語所示意的，是一組信息或數(shù)據(jù)。例子包含電話或電視信號(hào)，一個(gè)企業(yè)的月銷售，或股票市場(chǎng)的每天收盤價(jià)。在全部這些例子中，信號(hào)是獨(dú)立的時(shí)變函數(shù)。這并不是老是這樣，但是，當(dāng)電荷散布在一個(gè)物體上時(shí)，比如，該信號(hào)是電荷密度，它是空間而不是時(shí)間的函數(shù)。在這本書中，我們辦理的信號(hào)幾乎完好是時(shí)間的函數(shù)。但是，議論，相同合用于其余獨(dú)立的變量。In1876AlexanderGrahamBelltookthetelegraphonestepfurther.Ratherthanconvertingamessageintoasequenceofdotsanddashes,heshowedthatavoicecouldbeconverteddirectlytoelectricalenergyandtransmittedoverawireusingcontinuouslyvaryingvoltages.Atthewire’sotherendtheelectricalnvertedsignbacklsweretocosound.Theresultwasthataperson’svoicecouldbetransmittedelectronicallybetweentwopointsaslongasaphysicalconnectionexistedbetweenthem.Tomostpeoplewhoseliveswerebasedononlywhattheycouldseeandhear,thisinventionwasabsolutelyincredibleandseemedmagical.譯：在

1876年亞歷山大·格雷厄姆·貝爾促使了電報(bào)進(jìn)一步的發(fā)展。而不是將信息變換為一系列的點(diǎn)和破折號(hào)

,他表示,聲音能夠直接轉(zhuǎn)變成電能,經(jīng)過使用電線傳輸連續(xù)不一樣的電壓。線的另一端的電信號(hào)被變換回的聲音。結(jié)果是,一個(gè)人的聲音能夠在兩點(diǎn)之間流傳，只需它們之間存在一個(gè)物理連結(jié)。對(duì)大部分人來說,他們的生活是基于只有他們能看到和聽到的,這項(xiàng)發(fā)明絕對(duì)是令人難以置信的，仿佛是不行思議的。Anoperationalamplifier,oftencalledanop-amp,isaDC-coupledhigh-gainelectronicvoltageamplifierwithdifferentialinputsand,usually,asingleoutput.Typicallytheoutputoftheop-ampiscontrolledeitherbynegativefeedback,whichlargelydeterminesthemagnitudeofitsoutputvoltagegain,orbypositivefeedback,whichfacilitatesregenerativegainandoscillation.Highinputimpedanceattheinputterminalsandlowoutputimpedanceareimportanttypicalcharacteristics.譯：一個(gè)運(yùn)算放大器，往常被簡(jiǎn)稱為op-amp，是一個(gè)直流耦合、差分輸入、高增益的電壓放大器，往常，有一個(gè)單調(diào)的輸出。典型的運(yùn)算放大器的輸出是由負(fù)反應(yīng)控制，這在很大程度上決定了其輸出電壓增益的幅度，或許經(jīng)過正反應(yīng)，這有益于增添增益和振蕩。輸入端輸入阻抗高和輸出端輸出阻抗低是重要的典型特點(diǎn)。Withemail,itispossibletosendamessagetoremotelocationsfromtheprivacyofyourownhome.ApersonwithaPCandmodemathomecanaccesshisorhercompany’sorInternetServiceProvider’networkalsoconnectstoawideareanetworkthatallowsmessagetobesentacrossthecountryortoothercountries.LocalareanetworksattheotherendcanrouteatransmittedmessagetoanyconnectedPC.AnindividualonthatendwithaPCandmodemcanreceivethemessageathome.譯：電子郵件，使你在家里能夠向偏僻地域發(fā)送私密信息成為了可能。一個(gè)人在家里用電腦和調(diào)制解調(diào)器能夠接見他或她的企業(yè)或互聯(lián)網(wǎng)服務(wù)商供給的計(jì)算機(jī)。該計(jì)算機(jī)被連結(jié)到局域網(wǎng)，同意一個(gè)信息被發(fā)送到連結(jié)到它的任何人。局域網(wǎng)還連結(jié)到一個(gè)廣域網(wǎng)，它同意在全國(guó)或到其余國(guó)家要發(fā)送的信息。在另一端發(fā)送的信息能夠經(jīng)過路由局域網(wǎng)與任何計(jì)算機(jī)連結(jié)。個(gè)人能夠用個(gè)人電腦和調(diào)制解調(diào)器在家里接收到信息。Multimediaisacomputertechnology.Itsapplicationsinvolvetheintegratedprocessingofvarioustypesofdata,likesound,images,fullmotionvideo,graphics,characterdata,andetc.Now,multimediaapplicationshavebendevelopedfortraditionaluseslikecustomerservice,officeautomation,andcomputer-aidedinstruction.Inthemultimediaenvironment,wehavegraphicsandtextatthesametime,wecanalsoaddphotograph,animation,good-qualitysound,andfullmotionvideo,allofthetechnologiesmakecomputersmuchmorepowerfulandmucheasiertouse.譯：多媒體是計(jì)算機(jī)技術(shù)。它的應(yīng)用波及到各樣種類的數(shù)據(jù)的綜合辦理，如聲音，圖像，完好的動(dòng)向視頻，圖形，字符數(shù)據(jù)等。此刻，傳統(tǒng)的多媒體應(yīng)用已經(jīng)成熟，如客戶服務(wù)，辦公自動(dòng)化，計(jì)算機(jī)協(xié)助教課。在多媒體環(huán)境中，我們同時(shí)對(duì)圖形和文字進(jìn)行辦理，我們還能夠增添照片，動(dòng)畫，高質(zhì)量的聲音，和完好的動(dòng)向視頻，全部的技術(shù)使得計(jì)算機(jī)更強(qiáng)盛和更簡(jiǎn)單使用。Theoperationalamplifieristhemostimportantbasicblockofalllinearcircuits.Ithasawiderangeapplicationsinsuchfieldsasanaloguesignaloperations,amplification,filtering,waveformsproducing,linearandnon-linearsignalshanding,etc.譯：運(yùn)算放大器是全部線性電路中最重要的基本器件。它的應(yīng)用十分寬泛，包含模擬信號(hào)的運(yùn)算，放大，濾波，波形發(fā)生器，以及進(jìn)行線性和非線性信號(hào)的辦理等。Theterm“operationalamplifier”wasoriginallyappliedtohighgainamplifiersoperatingdowntozerofrequencywhichwereusedinanaloguecomputerstoperformcertainmathematicaloperations.Thesehighgainamplifierarenowusedforawidevarietyofapplications,butthename“operationalamplifiers-amp””orisnormally“opuseeventhoughnomathematicaloperationareinvolved.Theearlyoperationalamplifieremployeddiscretecomponents,butitisnowmuchmoreconvenienttoemployanintegratedcircuit.Thecircuitdesignersisnotgenerallyinterestedintheinternalcomponentsofanintegratedcircuit,butonlyintheperformanceoftheunitasawhole.Therefore,thesymbolinFig.2isusedtodenotetheamplifier.Itcanbeseenthattherearetwoinputs,oneoutputandconnectionthepositiveandnegativesupplylines.譯：