Talk:Nyquist stability criterion

message: I'm currently an EE student, and I posted this page as I learned the information in class. I feel that considering the highly-graphical nature of the Nyquist technique, this artical would benefit highly from some illustrations. however, i have not been able to find any illustrations that are free from copyright that could be used.
:: Added a much needed image. Musically ut 03:28, 27 March 2007 (UTC)
thread_title: Writing the Nyquist Criteria Artical

message: Could someone (more knowledgable in this general field than me at least) please rewrite the intro?? It makes no sense to the non-technical. Thanks.
Zidel333 11:44, 21 March 2006 (UTC)
thread_title:  Intro 

message: I am a Student of EE. And there seems to be a mistake in the criterion mentioned. I am looking forward to discussing the statement of the criterion with someone.
The mistake, I believe is here - "Given a Nyquist contour Γs, let P be the number of poles of F(s) encircled by Γs, and Z be the number of zeros of F(s) encircled by Γs -- therefore the number of poles of  enclosed by Γs. The resultant contour in the F(s)-plane, ΓF(s) shall, for a stable feedback system, encircle (clock-wise) the point (-1 + j0) N times such that N = Z − P."
For Stability Z,the number of closed loop poles, must be equal to zero.
And N = -P.
--Haditya 16:10, 26 January 2007 (UTC)
replies: text: This is a great opportunity to site a reliable source, so we can check you.  What source are you using? Dicklyon 16:55, 26 January 2007 (UTC)
replies: text: The book i am using is Norman Nise, Control Systems Engineering.
Alternately any other book on the subject should provide the same info.
other authors are Ogata, Modern Control Engineering
Kuo, Automatic Control Systems
Haditya 16:52, 2 February 2007 (UTC)

text: So fix the article add the citation. Dicklyon 18:30, 2 February 2007 (UTC)
thread_title:  Nyquist Stability Criterion 

message: The explanation seems complicated and is hard to visualise.  Could anyone explain how the Nyquist contour relates say to the plot in the provided example image of a Nyquist plot ? Rod57 (talk) 11:58, 19 October 2008 (UTC)
thread_title:  Nyquist Contour 

message: I've added this section because I am taking the course now, and there doesn't seem to be any good source on this; even textbooks seem to say "Cauchy's argument principle" and wave their hands as if suddenly all of this means something.  Sometimes, you just have to make your own sources.
I plan on enriching this page with some appropriate diagrams (probably matlab), maybe an example problem for good measure.  Maybe a bit on how to do this in matlab, even.  This page is going places.  Sometimes, the best way to study for a midterm is to become an authority on the subject.
We'll see how this develops.
oooh, signature.Bengski68 (talk) 06:17, 4 April 2013 (UTC)
thread_title: Mathematical Derivation

message: Would it be a terribly silly idea to mention this?
Q: Why do Eastern European airlines fly half empty?
A: There must be no poles in the right half-plane
Sources and variations:
http://unclecj.blogspot.com/2009/02/two-very-nerdy-jokes.html
http://users.ox.ac.uk/~invar/links/jokes.html
http://forum.darwincentral.org/viewtopic.php?f=47&t=34992&start=0#p632962
http://scienceblogs.com/goodmath/2009/06/defining_dynamical_systems.php#comment-1701610
CarlJohanSveningsson (talk) 09:35, 31 May 2010 (UTC)
thread_title:  Trivia: the joke