Main Content

Plot singular values of frequency response with additional plot customization options

`sigmaplot`

lets you plot the singular values (SV) of frequency
response of a dynamic system model with a broader range of plot customization options than
`sigma`

. You can use `sigmaplot`

to obtain the plot handle
and use it to customize the plot, such as modify the axes labels, limits and units. You can
also use `sigmaplot`

to draw an SV plot on an existing set of axes
represented by an axes handle. To customize an existing SV plot using the plot
handle:

Obtain the plot handle

Use

`getoptions`

to obtain the option setUpdate the plot using

`setoptions`

to modify the required options

For more information, see Customizing Response Plots from the Command Line. To create SV plots with default options or to extract
the frequency response data, use `sigma`

.

plots
the singular values (SV) of the frequency response of the dynamic system model
`h`

= sigmaplot(`sys`

)`sys`

and returns the plot handle `h`

to the plot. You
can use this handle `h`

to customize the plot with the `getoptions`

and `setoptions`

commands.

plots singular values for frequencies specified by the frequencies in
`h`

= sigmaplot(___,`w`

)`w`

.

If

`w`

is a cell array of the form`{wmin,wmax}`

, then`sigmaplot`

plots the singular values at frequencies ranging between`wmin`

and`wmax`

.If

`w`

is a vector of frequencies, then`sigmaplot`

plots the singular values at each specified frequency.

You can use `w`

with any of the input-argument combinations in
previous syntaxes.

See `logspace`

to generate logarithmically spaced
frequency vectors.

plots the modified singular value responses based on the `h`

= sigmaplot(___,`type`

)`type`

argument.
Specify `type`

as:

`1`

to plot the SV of the frequency response*H*, where^{-1}*H*is the frequency response of`sys`

.`2`

to plot the SV of the frequency response*I+H*.`3`

to plot the SV of the frequency response*I+H*.^{-1}

You can only use the `type`

argument for *square
systems*, that is, systems that have the same number of inputs and
outputs.

plots the singular values with the options set specified in
`h`

= sigmaplot(___,`plotoptions`

)`plotoptions`

. You can use these options to customize the SV plot
appearance using the command line. Settings you specify in `plotoptions`

overrides the preference settings in the MATLAB^{®} session in which you run `sigmaplot`

. Therefore, this syntax
is useful when you want to write a script to generate multiple plots that look the same
regardless of the local preferences.