Any way to mark (1+0j) in Nyquist diagram

Hi, I'm trying to mark (1+0j) and invalidate (-1+0j) in Nyquist diagram cuz I'm analyzing a positeve feedback system.I can't find any information about it on the reference.

Answer 1

[Bhavya Chopra]

I understand that you want to plot the points (1 + 0j) and (-1 + 0j) to mark them on the Nyquist plot. Consider the following Nyquist plot:

sys = tf(1,[1,1,1]);  
nyquist(sys);

The points (1, 0) and (-1, 0) can be marked on the plot as follows:

hold on;
plot(1, 0, "o")
plot(-1, 0, "o")
hold off;

[嵩人 藤森]

Thank you,

Much love