Difference between revisions of "Errata: In the paragraph above Example 9.3, G(*) should be L(*)"

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{{errata page
 
{{errata page
| chapter =  
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| chapter = Frequency Domain Analysis
| page =  
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| page = 272
| line =  
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| line = 10,11
| contributor = R. M. Murray
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| contributor = J. W. Kim
| date =  
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| date = 27 Nov 2011
| rev = 2.10e
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| rev = 2.11a
 
| version = Third printing
 
| version = Third printing
 
| text =  
 
| text =  
 +
For computing the Nyquist plot, it is the loop transfer function <amsmath>L(i\omega)</amsmath> that should be used.  The paragraph should read:
 +
<blockquote>
 +
An alternative to computing the Nyquist plot explicitly is to
 +
determine the plot from the frequency response (Bode plot), which
 +
gives the Nyquist curve for <amsmath>s = i \omega</amsmath>, <amsmath>\omega > 0</amsmath>.  We start by
 +
plotting <amsmath>{\color{blue}L}(i\omega)</amsmath> from <amsmath>\omega = 0</amsmath> to <amsmath>\omega = \infty</amsmath>, which
 +
can be read off from the magnitude and phase of the transfer function.
 +
We then plot <amsmath>{\color{blue}L}(R e^{i\theta})</amsmath> with <amsmath>\theta \in [-\pi/2, \pi/2]</amsmath> and <amsmath>R
 +
\to \infty</amsmath>, which almost always maps to zero.  The remaining parts of
 +
the plot can be determined by taking the mirror image of the curve
 +
thus far (normally plotted using a dashed line).  The plot can
 +
then be labeled with arrows corresponding to a clockwise
 +
traversal around the D contour (the same direction in which the first
 +
portion of the curve was plotted).
 +
</blockquote>
 
}}
 
}}

Latest revision as of 00:42, 29 September 2012

Return to Errata page

Location: page 272, line 10,11

For computing the Nyquist plot, it is the loop transfer function math that should be used. The paragraph should read:

An alternative to computing the Nyquist plot explicitly is to determine the plot from the frequency response (Bode plot), which gives the Nyquist curve for math, math. We start by plotting math from math to math, which can be read off from the magnitude and phase of the transfer function. We then plot math with math and math, which almost always maps to zero. The remaining parts of the plot can be determined by taking the mirror image of the curve thus far (normally plotted using a dashed line). The plot can then be labeled with arrows corresponding to a clockwise traversal around the D contour (the same direction in which the first portion of the curve was plotted).

(Contributed by J. W. Kim, 27 Nov 2011)