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Plotting the Nyquist Diagram - Stuck

  1. Apr 18, 2012 #1
    1. The problem statement, all variables and given/known data

    Okay, quite stuck here. Spent a few hours with the notes and tried some websites, but I'm still not confident in plotting Nyquist Diagrams
    2. Relevant equations
    N = Z-P

    3. The attempt at a solution
    Well, at w=0, gain is -2 and at w= ∞ gain = 0.

    We also have a pole at s=0.5 in the right half plane... so P=1, correct? As we have an unstable pole?

    As for the phase it goes from 0 to -90°. WHY is calculating the phase important, where is this show on the Nyquist plot!?

    Do I now have enough information to draw it?
    How would you go about drawing it?

    How do I know what values to the j-axis should take? How do I know if it's meant to loop around under the real axis and back up to (0,0)

    Many Thanks

    Last edited: Apr 18, 2012
  2. jcsd
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