phase margin measurement from transient plot

[vndjn]

phase margin measurement

Hi,
Is there any function in icfb to meaure phase margin from transient plot.

Thanks,

 

[surianova]

u must do in ac to see phase margin.

 

[northeast1]

Hi,
Is there any function in icfb to meaure phase margin from transient plot.

Thanks,

this cant be done, you can judge the phase marge from the transient plot of step response

 

[Alan_Nesta]

for a 2-pole system, you can use this idea.
And I think Step response is more important than PM for reality use.
for example when system has one dominant pole and 2 conjugate poles, or has zeros, PM may be good, but step response is very bad.

 

[vndjn]

Thanks,
from step response we know the overshoot and settling time, so i want to know can we get PM value by overshoot/settling.

 

[yxo]

Very easy get PM from: calculator =>ac >function PhaseMargin

Added after 5 minutes:

for a 2-pole system, you can use this idea.
And I think Step response is more important than PM for reality use.
for example when system has one dominant pole and 2 conjugate poles, or has zeros, PM may be good, but step response is very bad.

more precise, LARGE step response. Because transistor may leave saturation region