# 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 = | + | | chapter = Frequency Domain Analysis |

− | | page = | + | | page = 272 |

− | | line = | + | | line = 10,11 |

− | | contributor = | + | | contributor = J. W. Kim |

− | | date = | + | | date = 27 Nov 2011 |

− | | rev = 2. | + | | 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 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 , . We start by plotting from to , which can be read off from the magnitude and phase of the transfer function. We then plot with and , 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)