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科技英语课件ExercisesHMILYYLIMH1UUnniitt11EExxeerrcciisseess((11))TTrraannssllaatteetthheeffoolllloowwiinnggsseenntteenncceessiinnttooCChhiinneessee..1.Aswithseriesresonance,thegreatertheresistanceinthecircuitthelowertheQand,accordingly,theflatterandbroadertheresonancecurveofeitherlinecurrentorcircuitimpedance.对于串联谐振，电路中的电阻愈大Q值就愈低，相应地线路电流或电路阻抗的谐振曲线也就愈平、愈宽。2.Awirecarryingacurrentlooksexactlythesameandweighsexactlythesameasitdoeswhenitisnotcarryingacurrent.一根带电的导线其外表与重量都与不带电导线完全一样。3.Clickmouseonthewaveformanddragittochangethepulserepetitionrate,ordirectlyenteranewvalueoftheperiodintheprovideddialoguebox,whilekeepingthepulsewidthunchanged.在波形上点击鼠标并拖动来改变脉冲重复频率，或者在提供的对话框中直接输入新的周期值，而保持脉冲宽度科技英语课件ExercisesHMILYYLIMH2不变。4.Electronicsisthescienceandthetechnologyofthepassageofchargedparticlesinagas,inavacuum,orinasemiconductor.Pleasenotethatparticlemotionconfinedwithinametalonlyisnotconsideredelectronics.电子学是一门有关带电粒子在气体、真空或半导体中运动的科学技术。注意，在本书中粒子运动仅限于金属的情况不属于电子学。5.Hardwaretechnologieshaveplayedvitalrolesinourabilitytouseelectronicpropertiestoprocessinformation,butsoftwareanddataprocessingaspectshavenotdevelopedatthesamespeed.硬件技术在我们使用电子特性来处理信息的能力中一直起着重要作用，而软件及数字处理方面却没能与硬件同步发展。6.However,inaproperlydesignedDCamplifiertheeffectoftransistorparametervariation,otherthanIco,maybepracticallyeliminatediftheoperationpointofeachstageisadjustedsothatitremainsinthelinearoperationrange科技英语课件ExercisesHMILYYLIMH3ofthetransistorastemperaturevaries.然而在设计得当的直流放大器中，若调节每一级的工作点使之在温度变化时保持在晶体管线性区，就能在实际上消除Ico以外的晶体管参数变化所造成的影响。UUnniitt22EExxeerrcciisseess((11))TTrraannssllaatteetthheeffoolllloowwiinnggsseenntteenncceessiinnttooCChhiinneessee..1.Ifanalogsignalsaretobetransmitteddigitally,theyfirsthavetobesampledataspecifiedrateandfurtherconvertedtodiscreteamplitudesamplesbyquantization.如果要以数字方式传输模拟信号，首先必须以一定的频率对信号进行采样，然后通过量化进一步将它们转换为离散的幅度样本。2.Linearfiltersamplifyorattenuateselectedspatialfrequencies,canachievesucheffectsassmoothingandsharpening,andusuallyformthebasisofre-samplingandboundarydetectionalgorithms.线性滤波器放大或衰减选择的空间频率，能够实现像平滑和锐化这些效果，通常是重采样和边缘检测算法的基础。科技英语课件ExercisesHMILYYLIMH43.Stabilityandrepeatabilityarefundamentalattributesofdigitalcircuits,however,andthenecessaryaccuracycanbeobtainedinadigitalversionofthemodulatorbyanappropriatechoiceofwordlengthtorepresentthesignals.不过稳定性和可重复性是数字电路的基本性质，在数字式调制器中必要的精度可通过适当地选择代表信号的字长而获得。4.Thefirstobservationismadeonthefundamentalrelationshipbetweenthenatureofsystemandtheperiodicityofitsfrequencyresponse:acontinuoussystemhasanaperiodicfrequencyresponse,whileadiscretesystemhasaperiodicfrequencyresponse.从系统性质和它频率响应的周期性之间的基本关系中首先可以看到：连续系统有非周期性的频率响应，而离散系统有周期性的频率响应。5.Themainfunctionofthereceiveristoextracttheinputmessagesignalfromthedegradedversionofthetransmittedsignalcomingfromthechannel.接收器的主要功能是从由信道传输来的退化了的信号中提取出输入消息。科技英语课件ExercisesHMILYYLIMH5Unit3Exercises((11))TTrraannssllaatteetthheeffoolllloowwiinnggsseenntteenncceessiinnttooCChhiinneessee..1.Averycommonlyusedmethodofmicrowavemeasurementsisbasedonthestudyofastandingwavepatternformedalongthelinebecauseoftheinterferenceofincidentandreflectedwaves.一个很常用的微波测量方法是基于对驻波图型的研究，这种驻波是由入射波和反射波之间的干涉而沿着传输线形成的。2.Computationsshowareductionof6dBintheEMfieldintensitywiththedistancedoubled,andanincreaseof3dBintheintensitywiththetransmittedpowerdoubled.Thisresultprovidesverificationtothealgorithmused.计算表明，当距离增大一倍时，电磁场强度减小6分贝；而发射功率增大一倍时，场强则增加3分贝。这一结果验证了所用算法的正确性。3.Liketransferofheatbyconduction,convectionandradiation,microwaveheatingcanbeconsideredasanothermodeofheattransfer,inwhichheatisproduceddirectlyat科技英语课件ExercisesHMILYYLIMH6thelocationofthedielectriclosses.就像通过传导、对流、辐射来传递热量一样，微波加热可以看作热传递的另一种方式，即热量直接产生于发生介电损耗的地方。4.Operationoftheradarisbasedonthemeasurementofthetimeittakesforapulsetransmittedfromanantennatogetreflectedbytheobjecttobedetectedandtoreturnattheantennaandthereceiver.雷达的工作是基于对天线发出的脉冲被所要探测的目标反射，（然后）回到天线和接收机所需时间的测量。5.OthermotivationsforusingCADincircuitdesignincludesthewishtoacquireconfidenceinadesignthatwasaccomplishedbyothermeans,and,notleastinimportance,asenseofcuriosityorperhapsadesiretodiscovertheunexpected.在电路设计中使用CAD的其它动机包括：想要验证用别的方法设计出来的电路；满足好奇心或者可能是想发现预想不到的现象。后一个动机并非是最不重要的。（取得信心，并非最不重要，意料之外的事）科技英语课件ExercisesHMILYYLIMH76.Thespacingbetweentherepeatingamplifiersisafunctionofthecableattenuationandthesystembandwidthsothatthegainprovidedbytheseamplifierscompensatesforthelossintroducedbythecable.中继放大器之间的间距是电缆衰减和系统带宽的函数，以便这些放大器提供的增益补偿电缆引起的损耗。7.Whenthecut-offfrequencyisnolessthanthemaximalfrequencyoftheoriginalsignal,norisitgreaterthanthedifferencebetweenthesamplingfrequencyandthemaximalfrequency,theoriginalsignalmaybecompletelyrebuilt.当截止频率不小于原始信号的最高频率，也不大于采样频率和最高频率之差，原始信号可以完整地重建。8.WhilethepoliticsofthelastonehundredyearscenteredaroundIndustrialAgetechnology,thepoliticsofthefuturewillbebasedonInformationAgeconcernsorientedtowardsthestorage,protectionandexchangeofinformation.尽管近百年来的政治活动是以工业时代的技术为中心的，未来的政治活动将基于信息时代的事物，面向信息科技英语课件ExercisesHMILYYLIMH8的存储、保护和交换。UUnniitt44EExxeerrcciisseess((11))TTrraannssllaatteetthheeffoolllloowwiinnggppaassssaaggeessiinnttooCChhiinnee