t = 0:0.001:0.3;
x1 = 0.2*sin(2*pi*150*t); x1(t<=0.05 | t>=0.1) = 0;
x2 = 0.4*sin(2*pi*50*t); x2(t<=0.15 | t>=0.25) = 0;
x3 = sin(2*pi*10*t);
x = x1+x2+x3;
subplot(2,2,1)
plot(t,x1)
subplot(2,2,2)
plot(t,x2)
subplot(2,2,3)
plot(t,x3)
subplot(2,2,4)
plot(t,x)
