%  Figure 3.28      Feedback Control of Dynamic Systems, 5e
%                        Franklin, Powell, Emami
%script to generate Fig. 3.28
%  Example 3.25     

clf;
u=-1;  % magnitude of impulsive elevator input (Deg)
num=30*[1 -6];
den=[1 4 13 0];
t=0:.02:5;
y=impulse(u*num,den,t);
zero=[0 0];
tzero=[0 5];
axis([0 5 -2 16])
plot(t,y,'-',tzero,zero,'-'),grid
title('Fig. 3.28  Impulse response of aircraft altitude')
xlabel('Time (sec)')
ylabel('Altitude (ft)')
