Nyquist Criterion (Using Bode' Plots) Study Guide
(Links to material about the Nyquist Criterion for determining stability applying the criterion on Bode' plots)

        The Nyquist criterion is a method for determining stability of closed loop systems using frequency response information.  Nyquist stability analysis (i.e. applying the Nyquist Stability Criterion) is most often done using Bode' plots rather than a Nyquist plot even though the criterion is developed using reasoning about the Nyquist plot.