Nyquist Plot for 3 Real Poles and 3 Real Poles 1 Real Zero

Cuthbert Nyack
Applet shows the Nyquist plot and step response for 3 real(red, orange), 3 real poles and 1 real zero(green, pink) system. Since all systems are type 0, then plots start on the +ve real axis.
Third order starts in the first and ends in the third quadrant(phase from 0 to -270°) eg (2.0, 1.0, 1.0, 4.0, 1.0, 0.61).
eg parameters (2.9, 0.2, 1.0, 1.0, 5.0, 1.0, 1.18) show step response of 3p system being oscillatory at w = ~1.18.
(5.3, 0.2, 1.0, 1.0, 5.0, 1.0, 1.57) show step response of 3p1z system being oscillatory at w = ~1.57.
(3.8, 1.0, 1.0, 1.0, 1.4, 1.0, 1.44) show step response of 3p1z system having a phase margin of 60° at w = ~1.44 and a risetime of ~1.2s.
(2.2, 1.0, 1.0, 1.0, 1.4, 1.0, 0.83) show step response of 3p system having a phase margin of 60° at w = ~0.83 and a risetime of ~2.2s.
(2.0, 1.0, 1.0, 1.0, 0.9, 1.0, 1.05) show step response of 3p1z system having a phase margin of 90° at w = ~1.05 and a risetime of ~1.5s.




Gif image below shows how applet should appear.

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COPYRIGHT 2006 Cuthbert Nyack.