数字信号处理练习题14

1/4此题为考试题型提示及部分复习范围，全部考试范围为最后讲义及课堂所讲有关内容，1．Filltheblank(1).Thesamplerateisfs,theanalysisfrequenciesofm-thbininN-pointDFTis()Hz.(2).Usingfunctionofwindowcanreducetheripplelevel,butthe()iswidened.(3).Writeoutthethreemajorpropertyofunitimpulsefunction,(),(),().(4).TheCICfiltersareusedfor()filteringpriortodecimation,andfor()filteringforinterpolation.(5).FIRfilterdesigntechniqueinclude()methodand()method.(6).Bandpasssamplingisknownas()sampling,()sampling,()sampling,and()sampling.(7).Thedefinitionofgroupdelayis(),fornodistortionofphasethegroupdelayofsystemshouldbe().(8).Inquadratureprocessing,byconvention,therealpartofthespectrumiscalledthe()componentandtheimaginarypartofthespectrumiscalledthe()component.(9).TheGoertzelalgorithmusean()filtertocomputeasinglecomplexDFTspectralbinvalue.(10).ThemajormethodsofdesigningIIRfiltercontains:(),(),().(11).Ingeneralweuse()averaginginthefrequencydomainand()averaginginthetimedomainfornoisereduction.(12).Asuddenchangeinthevaluesofthecoefficientsequence,causes(ripples),or(sidelobes),inthefrequencyresponse.(13).ThetermsFIRfiltercoefficientsand(impulseresponse)aresynonymous.(14).Thefouriertransferofacomplexsinusoidtjetx0)(,)(jX=().(15).AnN-pointradix-2FFThasMstages(M=log2(N)),eachstagecomprises()butterflies.(16).WriteoutthethreeformofDirichletkernel’smagnitude()Xm.(),2/4(),().(17).ThemagnitudeoftheN-pointDFTresultsaredirectlyproportionalto(N),andtheDFT'sfrequencyresolutionis().(18).Therearethreemajorscategoriesoffinite-wordlengtherrorsthatplagueIIRfilterimplementationsinourlecture.Theyare()、()and().(19).Theimpulseinvariancemethodaresusceptibletoaliasingproblemsbecausepracticalanalogfilterscannotbeperfectly(band-limited).(20).Therecursiverunningsumfilter'sdifferenceequationis().2．Selecttherightanswer(1).Multiplyinganynumberonthecomplexpanelbyjresultsinrotating().A．clockwiseB．anticlockwise(2).Inthefollowingsystem,()islinearsystem.(y(n)istheoutputsequence,x(n)istheinputsequence)A．y(n)=x3(n)B．y(n)=x(n)x(n+2)C．y(n)=x(n)+2D．y(n)=x(n2)(3).Realsignalsincludes()spectralcomponents.A．positivefrequencyB．negativefrequencyC.positiveandnegativefrequency(4).TherealandimaginarycomponentsofFouriertransferofrealsequenceare().A．evenfunctionandoddfunctionB．oddfunctionandevenfunctionC．oddfunctionandoddfunctionD．evenfunctionandevenfunction(5).Twiddlefactor68W=()A．34WB．14W(6).ThewrongdescriptionoftheIIRfiltercharactersis()A．Theimpulseresponseh(n)isinfinite.B．ThestructureofIIRfiltermustberecursiveC．IIRfilterisalwaysstablefilterD．ThesystemfunctionH(z)ofIIRfilterhavepolesatfiniteZ-plane(0|z|∞)3.(a)Plotthequadrature-samplingblockdiagram.(b)TheinputspectrumisfXbq.Pleaseplotthespectraofsignalsinblankrespectively(fQfXfIfX,,,qi).3/4Thespectrawithinthein-phasephase(upper)signalpathThespectrawithinthequadraturephase(lower)signalpath4/44.(a)Writeoutexponentialaverager’stime-domaindifferenceequation.(b)Writeoutitsfrequencyresponse.(c)PlotthestructuresoftheexponentialaveragerinIIRfilterform.