Errata: In the paragraph above Example 9.3, G() should be L()

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).