stepinfo 2

s=tf([1000],[1 3 2 6592 36354 119894 230060 241392 120960]) S = stepinfo(s,'RiseTimeLimits',[0.05,0.95]) S = RiseTime: NaN SettlingTime: NaN SettlingMin: NaN SettlingMax: NaN Overshoot: NaN Undershoot: NaN Peak: Inf PeakTime: Inf it is obvious that this results appears when the denominator is bigger than the forth order what shall i do please answer....

Answer 1

[Walter Roberson]

The documentation shows a 5th order example, so the order must not be the total cause.

It would be worth testing with that example, in case there is something wrong with the calculations on your system.

[ahmed salama]

it is a 8th order and there is no problem with my system i think please try the problem in your matlab and see the answers

s=tf([1000],[1 3 2 6592 36354 119894 230060 241392 120960])

S = stepinfo(s,'RiseTimeLimits',[0.05,0.95])

[Walter Roberson]

Sorry, I do not have that toolbox, so I cannot try that myself.