通信与电子信息科技英语总.ppt

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1、ExercisesⅠ.PleasetranslatethefollowingwordsandphrasesintoChinese.1.samplefunction2.ensembleaverage3.physicalsignificance4.aFouriertransformpair5.deterministicwaveform6.inthelimit7.timeinvariant8.anupperfrequencylimit9.Parseval’stheorem10.randomp

2、ulses样本函数总体均值物理意义傅立叶变换对确定性波型在极限情况下时不变的频率上限巴塞瓦尔定理随机脉冲ExercisesⅡ.PleasetranslatethefollowingwordsandphrasesintoEnglish.1.随机过程2.统计平均3.随机变量4.自相关函数5.傅里叶变换6.功率谱密度7.概率密度函数8.高斯过程9.平稳过程10.统计独立randomprocessstatisticalaveragerandomvariableautocorrelation

3、functionFouriertransformpowerspectraldensityprobabilitydensityfunctiongaussianprocessastationaryprocessstatisticallyindependent11.时间平均(值)12.统计特性13.各态历经过程14.狄拉克函数timeaveragestatisticalcharacteristicergodicprocessdeltafunctionExercisesⅢ.Fillintheblank

4、swiththemissingword(s).1.Theensembleaverageswillbeidenticalthestatisticalaveragesandmayberepresentedbythesamesymbols.2.TheaveragesdeterminedbymeasurementsasinglesampleFunctionsuccessivetimeswillyieldatimeaverage,whichwerepresentasn2(t1).3.Suppose,

5、forexample,thatthestatisticalcharacteristicsofthesampleFunctionstheensemblewerechangingwithtime.4.Foritmayhappenthatwhileeachsamplefunctionisstationarytheindividualsamplefunctionsmaydifferstatisticallyoneanother.5.Asanextensionofthatresultweshallde

6、finethepowerspectraldensityofarandomprocessthesameway.withonatinfrominExercises6.ItisinteresttoinquirewhetherG(f)definedEq.(1.2)forarandomprocesshasaphysicalsignificancewhichcorrespondstothephysicalsignificanceofG(f)fordeterministicwaveforms.8.Hence

7、,ifweshouldselectsomesamplefunction,aknowledgeofthevalueofn(t)attimetwouldbenoassistanceimprovingourabilitytopredictthevalueattainedbythatsamesamplefunctionattimet+τ.9.Hence,wheneverwemakeanobservationormeasurementofthepulsewaveformwhichextendsadura

8、tionlongenoughsothattheaverageobservedpulseshape,suchastheiramplitudes,widths,andspacingsarerepresentativeofthewaveformgenerally,weshallfindthatEq.(1.12)applies.ofinofinoverExercises10.Letusselectasectionofthiswaveformwhichextends-T/2-T/2.11.Sincewe