zgrid

Generate z-plane grid of constant damping factors and natural frequencies

Description

example

zgrid generates a grid of constant damping factors from 0 to 1 in steps of 0.1 and natural frequencies from 0 to π in steps of π/10 for root locus and pole-zero maps. zgrid then plots the grid over the current axis. zgrid creates the grid over the plot without altering the current axis limits if the current axis contains a discrete z-plane root locus diagram or pole-zero map.

zgrid(zeta,wn) plots a grid of constant damping factor and natural frequency lines for the damping factors and normalized natural frequencies in the vectors zeta and wn, respectively. zgrid(zeta,wn) creates the grid over the plot if the current axis contains a discrete z-plane root locus diagram or pole-zero map. You can also plot frequency lines for non-normalized (true) frequencies using zgrid(zeta,wn/Ts), where Ts is the sample time.

Alternatively, you can select Grid from the context menu to generate the same z-plane grid.

zgrid(___,'new') clears the current axes first and sets hold on.

zgrid(AX,___) plots the z-plane grid on the Axes or UIAxes object in the current figure with the handle AX. Use this syntax when creating apps with zgrid in the App Designer.

Examples

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To see the z-plane grid on the root locus plot, type

H = tf([2 -3.4 1.5],[1 -1.6 0.8],-1)
H =
 
  2 z^2 - 3.4 z + 1.5
  -------------------
   z^2 - 1.6 z + 0.8
 
Sample time: unspecified
Discrete-time transfer function.
rlocus(H)
zgrid
axis equal

Input Arguments

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Damping ratio, specified as a vector in the same order as wn.

Normalized natural frequency, specified as a vector. You can also plot frequency lines for non-normalized (true) frequencies using zgrid(zeta,wn/Ts), where Ts is the sample time.

Object handle, specified as an Axes or UIAxes object. Use AX to create apps with zgrid in the App Designer.

See Also

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Introduced before R2006a