function[POT]=pot(g)
%Compute POT of tf
%POT=pot(g)
%-------------------------------------------------------|%
%|(C)2005 Bui Trung Hieu				|%
%|Website: www.khvt.com					|%
%|Email: matlab@khvt.com				|%
%-------------------------------------------------------|%
[y,t]=step(g);
gtxl=freqresp(g,0);
if(max(y)<=gtxl)
    sprintf('Khong co boc lo!');
    POT=0;
else
POT=(max(y)-gtxl)/gtxl;
end