浙江大学 信电系 信号与系统实验报告.doc

本科实验报告课程名称：信号与系统实验姓 名：院 系：专 业：学 号： 指导教师：周绮敏、史笑兴、李惠忠年 月 日实验时间： 周 第 节课签到表编号：专业：姓名：学号：日期：5.35.24地点：东四420室实验报告课程名称： 信号与系统实验 指导老师： 史笑兴、周绮敏、李惠忠 成绩：实验名称： 实验一 MATLAB基本实验 实验类型： 设计型 一、实验目的与要求1、掌握Matlab的基本使用方法：操作界面、基本语法、基本函数等；2、掌握Matlab在“信号与系统”课程中的应用：（1）信号的产生与表示；（2）产生基本信号的Matlab函数；（3）卷积和的计算与表示；（4）离散时间信号的傅立叶变换的计算与表示，部分傅立叶变换的性质验证。二、实验内容和原理1、P168，实验一，习题 1、2、3、4、5、72、P169，实验二，习题 1、1的补充题、2、33、P170，实验三，习题 1、2、3三、主要仪器设备带有matlab的电脑一台四、操作方法和实验步骤4.1 新建文本文档并命名，在文本文档中写matlab代码，另存为.m的文件，此时注意名称开头不应为数字，标题中不应出现matlab自带函数的名称；4.2打开matlab程序，运行已保存好的.m文件，根据提示的错误信息修改代码直至无错误为止，运行代码，记录运行结果。五、实验数据记录和处理实验1.1代码：clear;clf;clc;%Impulse sequencesubplot(2,2,1);n=-10:10;z=(n=0);stem(n,z);axis(-10,10,-1,2);title(Impulse sequence);xlabel(n);ylabel(deltan); %Impulse functionsubplot(2,2,2);t=-10:0.1:10;y=(t=0);plot(t,y,r);axis(-10,10,-1,2);title(Impulse function);xlabel(t);ylabel(delta(t); %Step Sequencesubplot(2,2,3);n=-10:10;z=(n=0);stem(n,z);axis(-10,10,-1,2);title(Step sequence);xlabel(n);ylabel(un); %Step functionsubplot(2,2,4);t=-10:0.1:10;y=(t=0);plot(t,y,b);axis(-10,10,-1,2);title(Step function);xlabel(t);ylabel(u(t);结果：实验1.2代码：%sine wavesubplot(2,2,1);t=-2*pi:pi/20:2*pi;plot(t,sin(t);axis(-2*pi,2*pi,-1.5,1.5);title(Sine wave);xlabel(t);ylabel(sin(t); %Triangular wavesubplot(2,2,2);t=-5*pi:pi/100:5*pi;x=sawtooth(t,0.5);plot(t,x);axis(-5*pi,5*pi,-1.5,1.5);title(Triangular wave);xlabel(t);ylabel(x); %Sawtooth wavesubplot(2,2,3);t=-5*pi:pi/100:5*pi;z=sawtooth(t,0);plot(t,z);axis(-5*pi,5*pi,-1.5,1.5);title(Sawtooth wave t=0);xlabel(t);ylabel(z); subplot(2,2,4);t=-5*pi:pi/100:5*pi;z=sawtooth(t,1);plot(t,z);axis(-5*pi,5*pi,-1.5,1.5);title(Sawtooth wave t=1);xlabel(t);ylabel(z);结果：实验1.3代码：clear;clf;clc;%Sinc functiont=-4*pi:pi/20:4*pi;subplot(2,1,1);plot(t,sinc(t);axis(-4*pi,4*pi,-0.5,1.5);title(Sinc function);grid on;xlabel(t);ylabel(sinc(t); %Sample functionsubplot(2,1,2);plot(t,sinc(t/pi);axis(-4*pi,4*pi,-0.5,1.5);title(Sample function);grid on;xlabel(t);ylabel(sa(t);结果：实验1.4代码：u1=stepseq(0,-5,20);u3=stepseq(5,-5,20);x=u1-u3;n=-5:20;h=delta(n-5);subplot(3,1,1);stem(n,x);axis(-5,20,0,1.2);title(xn);xlabel(n);ylabel(xn);subplot(3,1,2);stem(n,h);axis(-5,20,0,1.2);title(hn);xlabel(n);ylabel(hn);y,ny=conv_my(x,n,h,n)subplot(3,1,3);stem(ny,y);axis(-5,20,0,1.2);title(yn);xlabel(n);ylabel(yn);结果：实验1.5代码：n=-10:10;x1=delta(n);x2=delta(n+2);x3=delta(n-4);x4=2*delta(n+2)-delta(n-4);subplot(2,2,1);stem(n,x1);title(x_1n=deltan);axis(-10,10,-1,2);grid on;subplot(2,2,2);stem(n,x2);title(x_2n=deltan+2);axis(-10,10,-1,2);grid on;subplot(2,2,3);stem(n,x3);title(x_3n=deltan-4);axis(-10,10,-1,2);grid on;subplot(2,2,4);stem(n,x4);title(x_4n=2*deltan+2-deltan-4);axis(-10,10,-1,2);grid on;结果：实验1.7代码：clear;clf;clc;n=-15:15;x1=stepseq(0,-15,15);x2=stepseq(10,-15,15);x=x1-x2;xe,xo=evenodd(x);subplot(2,2,1);stem(n,x);title(Step sequence);xlabel(n);ylabel(xn);axis(-15.5,15.5,-1.2,2);subplot(2,2,3);stem(n,xe);axis(-15,15,-1,2);title(Even part);xlabel(n);ylabel(xen);axis(-15.5,15.5,-1.2,2);subplot(2,2,4);stem(n,xo);title(Odd part);xlabel(n);ylabel(xen);axis(-15.5,15,-1.2,1.2);结果：实验2.1代码：clear;clf;clc;n=-5:10;nx=-5:10;nh=-5:10;h=delta(n-5)*1.0;x=stepseq(0,-5,10)-stepseq(5,-5,10);y,ny=conv_m(x,nx,h,nh);subplot(3,1,1);stem(n,x);title(xn);xlabel(n);axis(-5,10,0,1.2);grid on;subplot(3,1,2);stem(n,h);title(hn);xlabel(n);axis(-5,10,0,1.2);grid on;subplot(3,1,3);stem(ny,y);title(yn);xlabel(n);axis(-10,20,0,1.2);grid on;结果：实验2.1补充题代码：u1=stepseq(5,-10,10);u3=stepseq(-5,-10,10);x=(abs(n)=0);subplot(3,1,1);stem(n,x);axis(-5,20,-1,2);title(xn);ylabel(xn);subplot(3,1,2);stem(n,h);axis(-5,50,-1,2);title(hn);ylabel(hn);y,ny=conv_m(x,n,h,n);subplot(3,1,3);stem(ny,y);axis(-10,70,-2,8);title(yn);xlabel(n);ylabel(yn);结果：实验3.1代码：clear;clc;clf;n=-20:20;x=stepseq(-5,-20,20)-stepseq(6,-20,20);w1=-2*pi;w2=2*pi;w_step=pi/400;w=w1:w_step:w2;ww=w/pi;xw=spec(x,n,w); %?w?subplot(2,2,1);plot(ww,abs(xw);axis(-2,2,0,max(abs(xw);grid on;xlabel(w);title(Abs(X);subplot(2,2,2);plot(ww,angle(xw);axis(-1.2,1.2,-1.2*pi,1.2*pi);grid on;xlabel(w);title(Phase(X);subplot(2,2,3);plot(ww,real(xw);axis(-2,2,min(real(xw),max(real(xw);grid on;xlabel(w);title(Real(X);subplot(2,2,4);plot(ww,imag(xw);axis(-2,2,min(imag(xw),max(imag(xw);grid on;xlabel(w);title(Imag(X);结果：实验3.2代码：n=0:100;x=cos(pi*n/2); py=exp(j*pi*n/4);y=py.*x; w = -pi : pi/800 : pi;ww=w/pi;xw=spec(x,n,w);yw=spec(y,n,w);subplot(2,2,1);plot(ww,abs(xw);title(Magnitude of X);grid;ylabel(|X|);xlabel(Normalized Freq.( rad/s);axis( min(ww) , max(ww) , 0, max(abs(xw) );subplot(2,2,2);plot(ww,angle(xw);title(Angle of X);grid;ylabel(Angle(X);xlabel(Normalized Freq.( rad/s);axis( min(ww) , max(ww) , -pi, pi );subplot(2,2,3);plot(ww,abs(yw);title(Magnitude of Y);grid;ylabel(|Y|);xlabel(Normalized Freq.( rad/s);axis( min(ww) , max(ww) , 0, max(abs(yw) );subplot(2,2,4);plot(ww,angle(yw);title(Angle of Y);grid;ylabel(Angle(Y);xlabel(Normalized Freq.( rad/s);axis( min(ww) , max(ww) , -pi, pi );结果：实验3.3代码：n=-5:10;x=sin(pi*n/2);w1=-pi;w2=pi;w_step=pi/800;w=w1:w_step:w2;X=spec(x,n,w);xe,xo,m=evenodd2(x,n); clf;XE=spec(xe,m,w);XO=spec(xo,m,w);XR=real(X);XI=imag(X);subplot(3,2,1);plot(w/pi,XR,r);grid;axis(-1,1,min(XR),max(XR);xlabel(Normalized Freq.(pi rad/sample);ylabel(ReX);title(Real part of X);subplot(3,2,2);plot(w/pi,XI,r);grid;axis(-1,1,min(XI),max(XI);xlabel(Normalized Freq.(pi rad/sample);ylabel(Im(X);title(Imaginary part of X);subplot(3,2,3);plot(w/pi,real(XE),r);grid;axis(-1,1,min(real(XE),max(real(XE);xlabel(Normalized Freq.(pi rad/sample);ylabel(XE or Re(XE);title(DFT of even part-real);subplot(3,2,4);plot(w/pi,imag(XE),r);grid;axis(-1,1,min(imag(XE),max(imag(XE);xlabel(Normalized Freq.(pi rad/sample);ylabel(Im(XE);title(DFT of even part-Imaginary);subplot(3,2,5);plot(w/pi,real(XO),r);grid;axis(-1,1,min(real(XO),max(real(XO);xlabel(Normalized Freq.(pi rad/sample);ylabel(Re(XO);title(DFT of oddd part-Real);subplot(3,2,6);plot(w/pi,imag(XO),r);grid;axis(-1,1,min(imag(XO),max(imag(XO);xlabel(Normalized Freq.(pi rad/sample);ylabel(XO/j or Im(XO);title(DFT of odd part-Imaginary);结果：子函数：1.stepseq.mfunction x,n=stepseq(n0,n1,n2)n=n1:n2;x=(n=n0);函数的功能是产生阶跃函数，其中n1和n2是函数的横坐标边界，n0是跳变点。2.evenodd.mfunction xe,xo=evenodd(x)xe=(x+fl