雨课堂学堂在线学堂云《Digital Signal Processing（辽宁科技）》单元测试考核答案

第1题Whichofthefollowingsystemsisacausalsystem?Ay(n)=x(n+2)By(n)=cos(n+1)x(n)Cy(n)=x(2n)Dy(n)=x(-n)第2题Thecorrectstatementamongthefollowingis()AThespectrumofacontinuousnon-periodicsignalisanon-periodiccontinuousfunctionBThespectrumofacontinuousperiodicsignalisanon-periodiccontinuousfunctionCThespectrumofadiscretenon-periodicsignalisanon-periodiccontinuousfunctionDThespectrumofadiscreteperiodicsignalisanon-periodiccontinuousfunction第3题Giventhesignalofxa(t)asshowninthefigure,itsFouriertransformismostlikely()ABCD第4题ThelinearpropertyoftheZtransformstatesthattheZtransformofthesumoftwosequencesisequaltothesumoftheirindividualZtransforms.()第5题IftheZtransformsoftwosequencesarethesame,thenthetwosequencesarealsothesame.()第6题TheinversetransformoftheZtransformisalwaysunique.()第7题Ifthesequenceiscausal,thentheconvergencedomainofitsZtransformcontainsatleasttheoutsideoftheunitcircle.()第8题TheconvergencedomainoftheZtransformalwayscontainstheunitcircle.()第9题TheZtransformisageneralizationofthediscrete-timeFouriertransform().()第10题Thesystemmustbeacausalsystem.()第11题Assumethatisaconstant,thenthesystemisalinearsystem.()第12题TheFouriertransformofasequencemustbeaperiodicfunction.()第13题Thepolesofthesystemfunctionofacausalandstablesystemmaybeoutsidetheunitcircle.()第14题Iftheoutputofacausalsystemattimendependsonlyontheinputsequenceattimenandbefore,andisindependentoftheinputsequenceaftertimen,thenthesystemissaidtohavecausalproperties,oriscalledacausalsystem.()第15题Whentheinputsequenceisdifferent,theunitsamplingimpulseresponseofthelinearshift-invariantsystemisalsodifferent.()第16题isacausalandunstablesystem.()第17题isalinearsystem.()第18题Asystemthatisbothadditiveandhomogeneousiscalledalinearsystem.()第19题Thesignalissampledatequalintervals,withasamplingperiodof,thenthefoldingfrequencyis200Hz.()第20题TheZtransformofasamplingsequenceontheunitcircleisequaltotheDTFTofthesamplingsequence.()第21题Given,thenistheinversetransformof.()第22题Theofthesequenceis1.()第23题Ifalineartime-invariantsystemiscausal,thenthenecessaryandsufficientconditionthattheunitsamplingresponsesequenceofthesystemshouldmeetand.()第24题Sinusoidalsequencesareallperiodicsequences.()第25题Astablediscrete-timesystemhasallitspoleslocatedoutsidetheunitcircleintheZplane.()第26题Themathematicalmodelofthelineartime-invariantsystemisthelinearconstantcoefficientdifferenceequation.()第27题Acertainsystemis,thenthesystemisalinearsystem.()第28题Giventhatthehighestfrequencyofasignalspectrumis100Hz,andtheminimumsamplingfrequencythatcanrestoretheoriginalsignalis200Hz.()第29题Themathematicalmodelofadiscrete-timesystemisadifferenceequation.()第30题Thesequencerepresentedbyisnotnecessarilyperiodic.()第1题WhatisFFTaformofDFT?()

AApproximatealgorithmBEfficientalgorithmCExactalgorithmbutmorecomplicatedDCompletelydifferentalgorithm第2题FromwhichdomaintowhichdomaindoesDFTtransformthesignal?()

AA.

TimedomaintofrequencydomainBFrequencydomaintotimedomainCComplexdomaintorealdomainDDiscretedomaintocontinuousdomain第3题Amongthefollowingphenomena,()doesnotbelongtothetruncationeffect.

ASpectrumleakage

BTimedomainaliasingCInter-spectralinterferenceDGibbseffect第4题WhichofthefollowingdescriptionsbestfitsthediscreteFouriertransformDFT?()AThetimedomainisadiscretesequence,andthefrequencydomainisalsoadiscretesequenceBThetimedomainisadiscretefinitesequence,andthefrequencydomainisalsoadiscrete

finitesequenceCThetimedomainisadiscreteinfinitesequence,andthefrequencydomainisacontinuousperiodicsignalDThetimedomainisadiscreteperiodicsequence,andthefrequencydomainisalsoadiscreteperiodicsequence第5题Indigitalsignalprocessing,fastFouriertransform()isoftenusedtocalculatecircularconvolutionbecauseitismuchmoreefficientthandirectlycalculatingcircularconvolution.()第6题Whenperformingcircularconvolution,ifthetwosequencesareofdifferentlengths,theymustfirstbepaddedwithzerostothesamelength.()第7题Ifthelinearconvolutionresultsoftwosequencesareuniquewithinacertainperiod,thentheircircularconvolutionisequaltothelinearconvolutionwithinthatperiod.()第8题Thelengthoftheresultofcircularconvolutionisalwaysequaltothelengthofthelongerofthetwosequences.()第9题Spectrumleakagedoesnotbelongtotruncationeffect.()第10题TherelationshipbetweentheconvolutionsumandthecircularconvolutionsumcanbeusedtoconvenientlycalculatethelinearconvolutionusingDFT.()第11题ChangethenumberofDFTpointstomakethespectrumlinesdenserandincreasethenumberoffrequencydomainsamplingpoints.Someoftheoriginallymissedspectramaybedetected.()第12题DecimationinfrequencyanddecimationintimearetwoequivalentFFToperations.()第13题Theoutputofthefrequencyextractionmethodisinnaturalorder,andtheinputisrearrangedaccordingtotheinversionrule.()第14题Thecomputationalcomplexityoftheoverlapretentionmethodandtheoverlapadditionmethodissimilar.()第15题DFTimpliesperiodicity.()第16题Periodicconvolutionistheperiodicextensionoflinearconvolution.()第17题istheequidistantsamplingvalueofontheunitcircle.()第18题DFThasfrequencyselectivecharacteristics.()第19题ThediscreteFouriertransformX()ofafinitelengthsequencex()istheZtransformofx()atanequidistantsamplingpointontheunitcircleoftheZplane.()第20题DFTistheFouriertransformofadiscretesequence.()第21题PeriodicsequencescannotundergoZtransform.()第22题DFTcanbeseenasaperiodofDFS.()第23题Thefirstperiodofaperiodicsequenceiscalledthe"mainvalueinterval".()第24题WhichofthefollowingstatementsaboutthepropertiesofdiscreteFouriertransform()iscorrect?()ADFTisalineartransformBDFThasimplicitperiodicityCDFTcanbeusedtoaccuratelyanalyzethespectrumofcontinuoussignalsDDFTcanberegardedasthesamplingofthesequenceztransformontheunitcircle正确答案：DAB第25题Whichofthefollowingdescriptionsabouttherelationshipbetweencircularconvolutionandlinearconvolutioniscorrect:()AWithoutzeropadding,thelengthofthecircularconvolutionisequaltothelengthoftheshortersequenceBIfthelengthsofthetwosequencesareequal,thentheircircularconvolutionisthesameasthelinearconvolutionCCircularconvolutionisanapproximationoflinearconvolutiononinfinitelengthsequencesDBypaddingzerosattheendofthesequence,circularconvolutioncanbemadeclosetolinearconvolution.正确答案：AD第26题Thepropertiesofcircularconvolutioninclude:()AItsatisfiesthecommutativeandassociativelawsBItslengthisequaltothesumofthelengthsofthetwosequencesminusoneCItcanbeefficientlycalculatedusingDFTandIDFT(inverseDFT)DItisequivalenttolinearconvolutionwhenthelengthislargeenough正确答案：AC第27题RegardingtheperiodicityofdiscreteFouriertransform(),whichofthefollowingstatementiscorrect?()ADFTisperiodicinthetimedomainBDFTisperiodicinthefrequencydomain,withaperiodofN(Nisthesignallength)CTheperiodicityoftheDFTmeansthatX(k)andX(k+N)arethesameDTheperiodicityofDFTisadirectresultofitsdefinition正确答案：DBC第28题InwhichofthefollowingfieldsdoesdiscreteFouriertransform()haveimportantapplications?()ASignalfilteringBSpectrumanalysisCCommunicationsystemDImageprocessing正确答案：DABC第29题Ifadiscrete-timesignalx()isreal-valuedandadiscreteFouriertransform()isperformed,then:()ATheamplitudespectrumofthetransformationresultX(k)issymmetricalBThephasespectrumofthetransformationresultX(k)issymmetricalCX(k)meetsconjugatesymmetry,thatis,X(Nk)=X*(k)DX(0)andX(N/2)(ifNiseven)arerealvalues正确答案：DAC第30题TherelationshipbetweendiscreteFouriertransform()andfastFouriertransform()is:()AFFTisanefficientimplementationalgorithmofDFTBFFTandDFTaremathematicallyequivalentCFFTcanonlybeusedforsignalswhoselengthisapowerof2DThecomputationalcomplexityofFFTisO(N^2),whereNisthelengthofthesignal正确答案：DABChapter4Exercises第1题ThetimecomplexityoftheFFTalgorithmis().

AO(n²)

BO(nlogn)

CO(n³)

DO(logn)第2题Operatea256-pointradix-2FFTdecimatedintimewith______butterfliesateachlevel.()A1024B1024×1024C512×10D1024×10第3题Theoperationflowgraphsymbolshowninthefigureisthebutterflyoperationflowgraphsymbolofthe_______radix-2FFTalgorithm.()ADecimationinfrequencyBDecimationintimeCBothAandBDNeitherAnorB第4题ThemainfunctionoffastFouriertransform(FFT)is().AImprovetheoperationspeedBReducetheoperationcomplexityCPerformspectrumanalysisonthesignalDAlloftheabove第5题ThenumberofcomplexmultiplicationsrequiredforanN-pointFFTis(N/2)log2N.()第6题Inthedecimation-in-timeFFToperationflowchartofN=32,5levelsofbutterflyoperationprocessarerequiredfromx()toX().()第7题ThenumberofcomplexmultiplicationsrequiredtodirectlycalculatetheN-pointDFTisproportionaltoN2.()第8题Thebase2FFTrequiresthenumberofpointsinthesequencetobe2L(whereLisaninteger).()第9题FFTcanbasicallybedividedintotwocategories:decimationintimeanddecimationinfrequency.()第10题FFTisafastalgorithmforDFT.()第11题FFTisanewtransform.()第12题Thebasicoperationunitoftheradix-2FFTalgorithmistheconvolutionoperation.()第13题Operationa256-pointradix-2FFTdecimatedintimewith64butterfliesateachstage.()第14题Tofindthe1024-pointradix-2FFTofthesequencex(),512×10complexmultiplicationsarerequired.()第15题TheoperationcomplexityofN-pointFFTisapproximatelytimescomplexmultiplicationandtimescomplexaddition.()第16题Inthedecimation-in-timeFFToperationflowchartofN=8,3levelsofbutterflyoperationprocessarerequiredfromx()toX().()第17题ThenumberofcalculationsfortheN-pointradix-2FFTofthesequencex()decimatedintimeisthesameasthenumberofcalculationsfortheradix-2FFTdecimatedinfrequency.()第18题TheadvantagesoffastFouriertransforminengineeringpracticeare().ASaveoperationtimeBReducehardwarecostsCImprovesignalprocessingqualityDFacilitatereal-timeprocessing正确答案：ABCD第19题WhattypesofsignalchangescanFFTbeusedtoanalyze?()A.FrequencychangeofthesignalB.AmplitudechangeoftheAPhasechangeofthesignalBTimechangeofthesignal正确答案：A第20题WhenperformingFFTcalculations,themeasuresthatcanbetakentoimprovecalculationaccuracyare().AIncreasethenumberofsamplingpointsBUseahigherprecisiondatatypeC.OptimizethealgorithmimplementationCReducethesignalamplitude正确答案：AB第21题WhichofthefollowingstatementsabouttherelationshipbetweenFFTanddiscreteFouriertransform()arecorrect.()AFFTisafastalgorithmforDFT.BTheresultsofFFTandDFTareexactlythesame.CFFTismoreefficientthanDFT.DFFTisonlyapplicabletosignalsofaspecificlength,whileDFTisapplicabletosignalsofanylength.正确答案：DABC第22题AfterperformingFFTprocessingonasignal,wecangetthesignal’s().AAmplitudespectrumBPhasespectrumCPowerspectrumDTimespectrum正确答案：ABC第23题TheimplementationmethodsoffastFouriertransformare().A.DecimationinTimeADecimationinFrequencyC.MixeddecimationmethodBRecursivealgorithm正确答案：AB第24题TheapplicationsofFFTincommunicationsystemsinclude().AModulationanddemodulationBChannelestimationCSignalfilteringDSignalencryption正确答案：ABC第25题WhichofthefollowingfactorswillaffecttheaccuracyofFFTresults?()ASamplingfrequencyBNumberofsamplingpointsCSignalnoiseDSignalamplitude正确答案：ABC第26题WhichofthefollowingtypesofsignalscanbeprocessedbyfastFouriertransform?()AContinuoussignalBDiscretesignalCPeriodicsignalDNon-periodicsignal正确答案：BCD第27题WhenusingfastFouriertransformforsignalprocessing,theproblemsyoumayencounterinclude().ASpectrumleakageBFenceeffectCOperationaccuracyDDatastorage正确答案：ABCD第28题RegardingthebutterflyoperationofFFT,whichofthefollowingstatementsarecorrect.()AItisthecoreoperationoftheFFTalgorithm.BIthasthecharacteristicsofparalleloperation.CItreducestheamountofoperation.DItisonlyapplicabletosequencesofaspecificlength.正确答案：ABC第29题IntheFFTalgorithm,thefactorsthataffecttheoperationefficiencyare().ASequencelengthBDatatype(realorcomplexnumber)CAlgorithmimplementationDComputerperformance正确答案：ABCD第30题ThefunctionsofInversefastFouriertransform()are().AConvertfrequencydomainsignalstotimedomainsignalsBInverseoperationofFFTCUsedforsignalreconstructionDImprovesignalresolution正确答案：ABCChapter5Exercises第1题WhichofthefollowingstatementaboutdesigningIIRfiltersusingtheimpulseresponseinvariancemethodisincorrect?().AThereisalinearrelationshipbetweendigitalfrequencyandanalogfrequencyBAbletomapalinearphaseanalogfiltertoalinearphasedigitalfilterCFrequencyaliasingeffectispronetooccurDCanbeusedtodesignhigh-passandband-stopfilters第2题ThecorrectstatementaboutdesigningIIRfilterusingbilineartransformationmethodis().AThereisalinearrelationshipbetweendigitalfrequencyandanalogfrequencyBAlwaysmapastableanalogfiltertoastabledigitalfilterCThetransformationusedisamulti-valuedmappingfromthesplanetothezplaneDNotsuitablefordesigninghigh-passandband-stopfilters第3题Assumethatthecutofffrequencyoftheideallow-passdigitalfilterisωc=π2

Thisfilterisobtainedbyconvertingtheideallow-passfilterusingtheimpulseresponseinvariancemethodatT=0.1ms.ThenthecutofffrequencyoftheanalogfilterisΩc=().A50πrad/sB500πrad/sC5000πrad/s

D50000πrad/s第4题AssumingthatananalogfilterHa()isahigh-passfilter,andmappedtoadigitalfilterH()throughs=z+1z−1

,thentheresultingdigitalfilterisa()filter.IfH()isalow-passfilter,thenH(-z)isa()filter.ALowpassB

PassiveCHighpassDActive第5题Thebilineartransformationmethodisanonlineartransformation,sousingittodesignIIRfilterscannotovercomethefrequencyresponsealiasingeffect.()第6题Theimpulseresponseinvariancemethodcannotbeusedtodesignhigh-passdigitalfilters.()第7题Thefrequencycoordinatetransformationofthebilineartransformationmethodisalinearrelationship.()第8题TheIIRfilterdesignedusingtheimpulseresponseinvariancemethodwillnotproducedistortion.()第9题Thepolesofacertainanalogfiltersystemfunctionarelocatedinthelefthalfplaneofthesplane.Whenitismappedtoadigitalfilterusingtheimpulseresponseinvariancemethod,thepolesoftheresultingdigitalfiltersystemfunctionarelocatedwithintheunitcircleofthezplane.()第10题Thebilineartransformationisamappingfromthesplanetothezplane.()第11题DesignanIIRdigitalhigh-passfilterwiththehelpoftheanalogfilter'sH().Ifnospecialrequirementsareemphasized,theimpulseresponseinvariancemethodshouldbeused.()第12题TheButterworthfilterhasamaximumflatamplitudecharacteristicwithinthepassbandanddecreasesmonotonically.()第13题Thedisadvantageofthepulseresponseinvariancemethodisthatitwillproducefrequencyaliasingphenomenon,andtheadvantageisthatωandΩareinalinearrelationship.()第14题IIRfiltersmustbelinearphase.()第15题InthebasicstructuresofIIRfilters,theparalleloperationhastheleastoperationerrorsandthehighestoperationspeed.()第16题InthebasicstructureofIIRfilter,thecascadeoperationhasmoreoperationerrors.()第17题InthebasicstructureofIIRdigitalfilter,thedirectoperationhasmoreoperationerrors.()第18题Theinfiniteimpulseresponse()filterhasafeedbackloopinitsstructure,soitisarecursivestructure.()第19题Digitalfrequencyisthenormalizationofanalogfrequencytosamplingfrequencyanditsvalueisdiscrete.()第20题Thefrequencyresponseofthedigitalfilterwhenrepresentsthehighfrequencyresponse.()第21题Thefrequencyresponseofthedigitalfilterwhenrepresentsthelowfrequencyresponse.()第22题Thebilineartransformationmethodisanonlineartransformation,sousingittodesignanIIRfiltercannotovercomethefrequencyaliasingeffect.()第23题Thefrequencydistortionproducedbythebilineartransformationmethodcannotbeovercome.()第24题Thebilineartransformationmethodisapplicabletoalltypesoffilterdesigns(low-pass,high-pass,band-pass,band-stop).()第25题UsethebilineartransformationmethodtodesignanIIRfilter.Theconversionofanalogangularfrequencytodigitalangularfrequencyisalinearconversion.()第26题Whenusingthebilineartransformationmethodtodesigndigitalfilters,pre-distortioncannoteliminatethenonlineardistortionofallfrequencypointsgeneratedduringthetransformation.()第27题Theimpulseresponseinvariancemethodisapplicabletoalltypesoffilterdesigns(low-pass,high-pass,band-pass,band-stop).()第28题Theimpulseresponseinvariancemethoddoesnotnecessarilymaptheminimumphaseanalogfiltertoaminimumphasedigitalfilter.()第29题Thebasicstructuresofinfiniteunitimpulseresponse()filtersaredirecttypeI,directtypeIIandparalleltype.()第30题WhenusinganalogfilterstodesignIIRdigitalfilters,theanalogprototypefiltersmainlyincludeButterworthfiltersandChebyshevfilters.()Chapter6Exercises第1题

HowmanytypesoflinearphaseFIRfiltersarethere?A1B2C3D4第2题ThesystemfunctionofaFIRfilteris,thenthesystembelongsto()AEven-symmetriclinearphasefilterwithoddNBOdd-symmetriclinearphasefilterwithoddNCEven-symmetriclinearphasefilterwithevenNDOdd-symmetriclinearphasefilterwithevenN第3题Whenonlythesameamplitude-frequencycharacteristicsarerequired,theorderoftheIIRfiltermustbelowerthantheFIRorder.()第4题OnlyFIRfilterscanachievelinearphase,whileIIRfilterscannotachievelinearphase.()第5题WhendesigningFIRdigitalfiltersusingthewindowfunctionmethod,increasingthelengthofthewindowfunctioncanreducethewidthofthetransitionband,andchangingthetypeofwindowfunctioncanchangethestopbandattenuation.()第6题ThedifferencebetweendesigningFIRdigitalfiltersusingthewindowfunctionmethodanddesigningFIRdigitalfiltersusingthefrequencysamplingmethodisthattheformerisperformedinthetimedomainandthelatterisperformedinthefrequencydomain.()第7题WhendesigningFIRdigitalfiltersusingthefrequencysamplingmethod,thebasicideaistosamplethespectrumoftheidealdigitalfiltertoobtainthediscretevaluesoftheactualdesignedfilterspectrum.()第8题FIRfiltersmusthavelinearphase,whileIIRfiltersmostlyhavenonlinearphase-frequencycharacteristics.()第9题ThebasicstructureofFIRfilterhasthesamebasicoperationunittypeasthebasicstructureofIIRfilter.()第10题ThesystemfunctionofacertainFIRdigitalfilteris,thenthissystemisnotalinearphasesystem.()第11题FIRfiltersmustbestable.()第12题SimilartoFIRfilters,IIRfilterscanalsoeasilyachievelinearphase.()第13题WhendesigningFIRfilterusingwindowmethod,themainreasonaffectingthequalityoffilteramplitude-frequencycharacteristicsisthatthemainlobemakesthedigitalfilterhavetransitionband,andthesidelobemakesthedigitalfilterhavefluctuation,reducingstopbandattenuation.()第14题Thezerodistributioncharacteristic