数字信号处理大作业分析

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1、数字信号处理大作业电子工程学院M2.2ThesquarewaveandthesawtoothwavearetwoperiodicsequenceassketchedinFigureP2.1.UsingthefunctionssawtoothandsquarewriteaMATLABprogramtogeneratetheabovetwosequencesandplotthemandtheperiodN.Forthesquarewavesequenceanadditionaluser-specifiedparame

2、teristhedutycycle,whileisthepercentoftheperiodforwhichthesignalispositive.Usingthisprogramgeneratethefirst100samplesofeachoftheabovesequenceswithasamplingrateof20khz,apeakvalueof7,aperiodof13andadutycycleof60%forthesquarewave.如下为matlab程序代码：%getuserinputsa=inp

3、ut('thepeakvalue=');l=input('lengthofsequence=');n=input('theperiodofsequence');ft=input('thedesiredsamplingfrequency=');dc=input('thesquarewavedutycycle=');%creatsingalst=1/ft;t=0:l-1;x=a*sawtooth(2*pi*t/n);y=a*square(2*pi*(t/n),dc);%poltsubplot(211)stem(t,x

4、)ylabel('Amplitude');xlabel(['Timein',num2str(t),'sec']);subplot(212)stem(t,y);ylabel('Amplitude');xlabel(['Timein',num2str(t),'sec']);在仿真之前，分析题目中所给出的数据，需要注意此时的周期为序列的个数13，而非时间周期13s，否则100个取样最终时间才花费0.05s，在图中就无法显示出来。同时占空比很明确的影响方波的取样正负所占比例，这也与占空比所本意相吻合。周期的多少也直接影响

5、一个周期内取样的个数。M2.4(a)WriteaMatlabprogramtogenerateasinusoidalsequencex[n]=Acos(ω0n+φ）andplotthesequenceusingthestemfunction.TheinputdataspecifiedbytheuserarethedesiredlengthL,amplitudeA,theangularfrequencyω0,andthephaseφwhere0<ω0<πand0≤φ≤2π.Usingtheprogramgenera

6、tethesinusoidalsequenceshowninfigure2.15.(b)Generatesinusoidalsequenceswiththeangularfrequenciesgiveninproblem2.2.Determinetheperiodofeachsequencefromtheplotandverifytheresulttheoretically.Answer:如下为matlab代码：>>L=input('Desiredlength=');A=input('Amplitude=');o

7、mega=input('Angularfrequency=');phi=input('Phase=');n=0:L-1;x=A*cos(omega*n+phi);stem(n,x);xlabel('Timeindex');ylabel('Amplitude');title(['omega_{o}=',num2str(omega)]);%%example：Desiredlength=100Amplitude=1.5Angularfrequency=0.1*piPhase=0ω0=0.1πω0=0.14π由理论计算

8、可知其周期t=2pi/0.14pi=100/7，故时间周期T=100，由图中也可明显看出，其波形以100开始循坏，故其周期也为100，相符。.ω0=0.24π理论计算t=2pi/0.24pi=25/3，故其周期为25，由图中也可看出，其图像每25一循坏，周期为25，与理论也相符。w0=0.34pi理论计算t=2pi/0.34pi=100/17，故其周期为100，由图中，基