Berti wrote on Feb 15th, 2011, 1:07am:Alexandar,
The simple bode stability does not apply in all cases. Most real system however are simple enough that they can be analyzed using the bode stability criterion. On the other hand, conditionally stable systems for instance (like the amplifiers design by Xignal for their CT Sigma-Delta) need to be analyzed using the Nyquist diagram.
I therefore think that Rakesh's question whether bode stability criterion is enough or the Nyquist plot has to be drawn is not that trivial ... and often ignored in classical text books!
Regards
FYI.. Bode plots and Nyquist plots show exactly the same information. It does not mean that if <insert some layman rule> does not apply, we need to use a Nyquist plot. Imho best to use is the complex plane w/ rootlocus method.
BTW strong nonlinear dynamics can be solved using the phase plane, that is if u are really interested into going the theoretical way. These are NOT Nyquist plots...