ex_3.m

信号与系统分析以matlab实现

%例4
clear all
syms t
f=maple('heaviside(t+3)-2*heaviside(t)');
t1=-5:0.01:5;
ff=subs(f,t,t1);
figure(1)
plot(t1,ff),axis([-5,5,-1.2,1.2]),title('u(t+3)-2u(t)')
t=-5:0.01:5;
f=heaviside(t+3)-2*heaviside(t);
figure(2)
plot(t,f),axis([-5,5,-1.2,1.2]),title('u(t+3)-2u(t)')
t=-5:0.01:5;
f=(1/2+1/2*sign(t+3))-2*(1/2+1/2*sign(t));
figure(3)
plot(t,f),axis([-5,5,-1.2,1.2]),title('u(t+3)-2u(t)')