Hi,

I'm using stability analysis (Spectre) to get loop gain plot(magnitude, phase, Nyquist plot) to check stability.

When I want to check stability through Nyquist plot, the number of encirclement of (-1,0)  equals
P(RHP poles of loop gain also RHP poles of (1+loop gain)) - Z(RHP zeros of (1+loop gain )).

If there are RHP poles, the number of encirclement of (-1,0) will not be zero to make sure there are no RHP zeros(stable system).

"How can I get the position of poles and zeros of loop gain after stb analysis?"
I tried to recognize them from bode plot, but failed(it's too complicated).

Otherwise, if using pole-zero analysis in Spectre, the loop needs to be broken. As I know, it's not a good idea to do so in a closed loop system.(that's why we are using stb analysis)

Thanks.