信号与系统——MATLAB基本实验

信号与系统MATLAB实践第一次上机作业实验一、熟悉MATLAB基本操作三、基本序列运算1.数组的加减乘除和乘方运算A=1 2 3;B=4 5 6;C=A+B;D=A-B;E=A.*B;F=A./B;G=A.B;subplot(2,4,1);stem(A)subplot(2,4,2);stem(B)subplot(2,4,3);stem(C)subplot(2,4,4);stem(D)subplot(2,4,5);stem(E)subplot(2,4,6);stem(F)subplot(2,4,7);stem(G)2.绘制函数波形（1）t=0:0.001:10x=3-exp(-t);plot(t,x)ylabel(f(t);xlabel(t);title(1);（2）t=0:0.001:10x=5*exp(-t)+3*exp(-2*t);plot(t,x)ylabel(f(t);xlabel(t);title(2);（3）t=0:0.001:3x=exp(-t).*sin(2*pi*t);plot(t,x)ylabel(f(t);xlabel(t);title(3);（4）t=0:0.001:3x=sin(3*t)./(3*t);plot(t,x)ylabel(f(t);xlabel(t);title(4);（5）k=1:1:6x=(-2).(-k);stem(k)xlabel(k);ylabel(f(k);title(5);（6）k=0:1:4x=exp(k);stem(k)xlabel(k);ylabel(f(k);title(6);（7）k=1:1:99x=k;stem(k)xlabel(k);ylabel(f(k);title(7);四、利用MATLAB求解线性方程组。1. a=2 3 1;1 1 1;3 -1 -1;b=11 6 -2;x=inv(a)*bx = 1.0000 2.0000 3.00002. a=1 1 1;1 -2 1;1 2 3;b=2 -1 -1;x=inv(a)*bx = 3.0000 1.0000 -2.00003. a=1 1 0;0 1 1;1 0 1;b=27 33 30;x=inv(a)*bx = 12 15 18实验二、信号的运算二、编写实现下列离散信号运算函数的程序，并画出波形。1. k=0:100x=sin(k);stem(x)xlabel(k);ylabel(f(k);title(2);2. k=0:100x=sin(k)+sin(pi*k);stem(x)xlabel(k);ylabel(f(k);title(2);3. k=3:103x=k.*sin(k);stem(x)xlabel(k);ylabel(f(k);title(3);4. function f=fun(k)for i=1:100 k(i)=i-50; if k(i)-pi)&(t(i)0)&(t(i)pi) y(i)=pi-t(i);else y(i)=0endend%new111.mclear allclcfor i=1:1000 w(i)=(i-1)/25; F= (t) fun111(t).*exp(-j*w(i).*t); G(i)=quad(F,0,1);endsubplot(1,2,1);plot(w,abs(G);xlabel(w);ylabel(G);title(数值计算幅度频谱);subplot(1,2,2);plot(w,angle(G);xlabel(w);ylabel(Fi);title(数值计算相位频谱);DFT法%fun1.mfunction y=fun1(x)if(-pix) & (x0) y=pi+x;elseif (0x) & (xpi) y=pi-x;else y=0end%new.mclear allclcfor i=1:1000 g(i)=fun1(2/1000*i-1); w(i)=(i-1)*0.2*pi;endfor i=1001:10000 g(i)=0; w(i)=(i-1)*0.2*pi;endG=fft(g)/1000;subplot(1,2,1);plot(w(1:50),abs(G(1:50);xlabel(w);ylabel(G);title(DFT幅度频谱);subplot(1,2,2);plot(w(1:50),angle(G(1:50)xlabel(w);ylabel(Fi);title(DFT相位频谱);2.数值计算%fun222.mfunction y=fun222(t)M,N=size(t);for i=1:Nif (t(i)-1) y(i)=cos(pi*(t(i)/2);else y(i)=0;endend%new222.mclear allclcfor i=1:1000 w(i)=(i-1)/25; F= (t) fun222(t).*exp(-j*w(i).*t); G(i)=quad(F,0,1);endsubplot(1,2,1);plot(w,abs(G);xlabel(w);ylabel(G);title(数值计算幅度频谱);subplot(1,2,2);plot(w,angle(G);xlabel(w);ylabel(Fi);title(数值计算相位频谱);DFT法%fun2.mfunction y=fun2(x)if x-1 y=cos(pi*x/2);else y=0;end%new2.mfor i=1:1000 g(i)=fun2(2/1000*i-1); w(i)=(i-1)*0.2*pi;endfor i=1001:10000 g(i)=0; w(i)=(i-1)*0.2*pi;endG=fft(g)/1000;subplot(1,2,1);plot(w(1:50),abs(G(1:50);xlabel(w);ylabel(G);title(幅度频谱);subplot(1,2,2);plot(w(1:50),angle(G(1:50)xlabel(w);ylabel(Fi);title(相位频谱);3数值计算%fun333.mfunction y=fun333(t)M,N=size(t);for i=1:Nif (t(i)-1) y(i)=1;elseif t(i)0 & t(i)1 y(i)=-1;else y(i)=0;endendend%new333.mclear allclcfor i=1:1000 w(i)=(i-1)/25; F= (t) fun333(t).*exp(-j*w(i).*t); G(i)=quad(F,0,5);endsubplot(1,2,1);plot(w,abs(G);xlabel(w);ylabel(G);title(数值计算幅度频谱);subplot(1,2,2);plot(w,angle(G);xlabel(w);ylabel(Fi);title(数值计算相位频谱);DFT法%fun3.mfunction y=fun3(x)if x-1 y=1;elseif x0 & x1 y=-1;else y=0end%new.mfor i=1:1000 g(i)=fun3(2/1000*i-1); w(i)=(i-1)*0.2*pi;endfor i=1001:10000 g(i)=0; w(i)=(i-1)*0.2*pi;endG=f