% ERROR STEP RESPONSE WITH ADDED POLE
%  Compare to Fig. 6.14
% alpha = 1, zeta = 0.5, Wn = 1 
%  rn: ratio of natural frequency to added pole

t = linspace(0,10,100);

clg; rn = 0
while (rn >= 0)
num = [rn 1 0 0];
den = [rn 1 1 1];
step(num,den,t);
grid;
rn = input('enter ratio of Wn to added pole (negative to quit) ')
end % while


