User`s guide

nichols
11-150
When i nvoked with left-hand arguments,
[mag,phase,w] = nichols(sys)
[mag,phase] = nichols(sys,w)
return the magnitude and phase (in degrees) of the frequency response at the
frequencies
w (in rad/sec). The outputs mag and phase are 3-D arrays similar to
those produced by
bode (see bode on page 11-19). They have dimensions
Remark If sys is an FRD model, nichols(sys,w), w can o nly include frequencies in
sys.frequency.
Example Plot the Nichols response of the system
num = [–4 48 –18 250 600];
den = [1 30 282 525 60];
H = tf(num,den)
nichols(H); ngrid
number of outputs
()
number of inputs
()×
length of
w()×
Hs()
4s
4
– 48s
3
18s
2
– 250s 600+++
s
4
30s
3
282s
2
525s 60++ ++
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