Getting to know simulation - Part8 - Arranging bode plot for AC analysis

1.       The best way to do AC stability analysis to plot Aforw vs 1/beta, plot of 1/beta essentially is the inversion of the beta gain – which is input/output instead of output/input – so let’s reverse the bode plot  and rename the block as shown

2.       So now you can see that the 40dB per decade closure of Aforw and 1/beta is the cause for oscillation