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Function Reference: damp

Function File: damp(sys)
Function File: [Wn, zeta] = damp(sys)
Function File: [Wn, zeta, P] = damp(sys)

Calculate natural frequencies, damping ratios and poles.

If no output is specified, display overview table containing poles, magnitude (if sys is a discrete-time model), damping ratios, natural frequencies and time constants.

Inputs

sys
LTI model.

Outputs

Wn
Natural frequencies of each pole of sys (in increasing order). The frequency unit is rad/s (radians per second). If sys is a discrete-time model with specified sample time, Wn contains the natural frequencies of the equivalent continuous-time poles (see Algorithms). If sys has an unspecified sample time (tsam = -1), tsam = 1 is used to calculate Wn.
zeta
Damping ratios of each pole of sys (in the same order as Wn). If sys is a discrete-time model with specified sample time, zeta contains the damping ratios of the equivalent continuous-time poles (see Algorithms). If sys has an unspecified sample time (tsam = -1), tsam = 1 is used to calculate zeta.
P
Poles of sys (in the same order as Wn).

Algorithm

Pole
Poles s (or z for discrete-time models) are calculated via pole and resorted in order of increasing natural frequency.
Equivalent continuous-time pole
s = log (z) / sys.tsam (discrete-time models only)
Magnitude
mag = abs (z) (discrete-time models only)
Natural Frequency
Wn = abs (s)
Damping ratio
zeta = -cos (arg (s))
Time constant
tau = 1 / (Wn * zeta)

See also: dsort, esort, @lti/pole, pzmap, @lti/zero

Source Code: damp