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2.5 Graphics 91
Animating Root Locus Plots
Sometimes it is helpful to animate a root locus plot because this shows the orientations of the
pole and zero trajectories better than a static plot. Let’s demonstrate root locus plot animation on
the transfer function H4[s, a] from above. To prepare the animation we compute a sequence of
pole-zero plots with identical plot ranges by mapping the following RootLocusPlot function to a
table of parameter values ranging from to in steps of . This is necessary because we want to
produce one separate plot in every parameter step instead of one single plot in which the solutions
from all steps are superimposed.
In[16]:= RootLocusPlot[H4[s, a], {a, #, #},
PoleStyle −> CrossMark[0.03, Hue[0.7] &,
Thickness[0.007]],
ZeroStyle −> CircleMark[0.03, Hue[0.3] &,
Thickness[0.007]],
PlotRange −> {{−6, 1}, {−4, 4}},
ShowLegend −> False,
LinearRegionStyle −> RGBColor[1, 1, 1]
] & /@ Table[x, {x, −3, 5, 2}]
a = 5.000e0
Im s
2.0E0
1.
-5.0E0 -2.0E0 -1. 1.
Re s
-1.
-2.0E0
Out[16]=
Graphics , Graphics , Graphics , Graphics , Graphics
We show only one plot here; several plots are generated if the command is evaluated in a Mathematica
notebook.
To animate the root locus plot double-click on one of the images. Alternatively, you can select
the resulting group of notebook cells containing the images with your mouse and then click on
Cell | Animate Selected Graphics in Mathematica’s frontend menu.
2.5.5 Transient Waveforms
For displaying transient waveforms, Analog Insydes provides the command
TransientPlot (Section 3.9.6). The usage of this function is demonstrated in Section 2.7.1 and
Section 2.7.6.