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Functions List

Function Reference: nichols

Function File: nichols (sys)
Function File: nichols (sys1, sys2, …, sysN)
Function File: nichols (sys1, sys2, …, sysN, w)
Function File: nichols (sys1, 'style1', …, sysN, 'styleN')
Function File: [mag, pha, w] = nichols (sys)
Function File: [mag, pha, w] = nichols (sys, w)

Nichols chart of frequency response, plots gain over phase. If no output arguments are given, the response is printed on the screen together with a grid of contours of constant close-loop magnitude and phase.

Inputs

sys

LTI system. Must be a single-input and single-output (SISO) system.

w

Optional vector of frequency values. If w is not specified, it is calculated by the zeros and poles of the system. Alternatively, the cell {wmin, wmax} specifies a frequency range, where wmin and wmax denote minimum and maximum frequencies in rad/s.

’style’

Line style and color, e.g. ’r’ for a solid red line or ’-.k’ for a dash-dotted black line. See help plot for details.

Outputs

mag

Vector of magnitude. Has length of frequency vector w.

pha

Vector of phase. Has length of frequency vector w.

w

Vector of frequency values used.

See also: bode, nyquist, sigma

Source Code: nichols

Example: 1

  

 s = tf('s');
 g = 1/(2*s^2+3*s+4);
 nichols(g);
plotted figure