matlab - e2

f1 = [-2.5:0.001:2.5];
y1 = 4*sinc(2*f1).^2 - (sinc(f1)).^2;
t = [-4:0.2:4];
subplot(2,1,1)
plot(f1, abs(y1))
subplot(2,1,2)
y2 = [zeros(1,10), [0:0.2:1], ones(1,9), [1:-0.2:0], zeros(1,10)];
plot(t,y2)