信号与系统实验一.doc

信号与线性系统实验报告一实验目的熟悉常见信号的意义、特性及波形。学会使用MATLAB表示信号的方法并绘制信号波形。掌握使用MATLAB进行信号基本运算的指令。熟悉用MATLAB实现卷积积分的方法。实验内容题目一:分别用MATLAB绘出下列连续时间信号的波形(1)(2)(3) (4)答:程序:程序如下所示。%构建变量区间及函数f11、f12、f13、f14t1=-5::10;f11=(2-exp(-2*t1)).*heaviside(t1);f12=cos(pi*t1/2).*(heaviside(t1)-heaviside(t1-4));f13=exp(t1).*cos(t1).*heaviside(t1);f14=2/3.*t1.*heaviside(t1+2);%将四个函数分别画在一张图的四个窗口中figure(1);subplot(2,2,1);plot(t1,f11);title('f(t)=(2-exp(-2*t))*heaviside(t)');xlabel('t');ylabel('f(t)');gridon;subplot(2,2,2);plot(t1,f12);title('f(t)=cos(pi*t/2)*[heaviside(t)-heaviside(t-4)]');xlabel('t');ylabel('f(t)');gridon;subplot(2,2,3);plot(t1,f13);title('f(t)=exp(t)*cos(t)*heaviside(t)');xlabel('t');ylabel('f(t)');gridon;subplot(2,2,4);plot(t1,f14);title('f(t)=2/3*t*heaviside(t+2)');xlabel('t');ylabel('f(t)');gridon;图片:图片如图1所示。图1题目二:分别用MATLAB表示并绘出下列离散时间信号的波形:(1)(2)答:程序:程序如下所示。%构建变量区间及函数f21、f22k2=-5:10;f21=(-).^k2.*heaviside(k2);f22=k2.*(heaviside(k2)-heaviside(k2-8));%将两个函数分别画在一张图的两个窗口中figure(1);subplot(1,2,1);stem(k2,f21);title('f(k)=(-)^k2*heaviside(k2)');xlabel('k');ylabel('f(k)');gridon;subplot(1,2,2);stem(k2,f22);title('f(k)=k2*[heaviside(k2)-heaviside(k2-8)]');xlabel('k');ylabel('f(k)');gridon;图片:图片如图2所示。图2题目三:已知信号f(t)的波形如下图3所示,试用MATLAB绘出满足下列要求的信号波形:图3(1)(2)答:程序:f(t)波形的程序如下。t=-1::3;fc=2.*heaviside(t)-heaviside(t-1)-heaviside(t-2);figure(1);plot(t,fc);gridon;xlabel('t');ylabel('f(t)');axis([-1,3,0,3