
Calling Sequence


PhasePlot(sys, opts)


Parameters


sys



System; system object to plot

opts



(optional) equation(s) of the form option = value; specify options for the PhasePlot command





Options


•

In addition to the following options, the PhasePlot command takes many of the standard plot options; see plot,options.


Specifies whether the frequencies are determined adaptively. The adaptive algorithm takes the value of the linearfreq option into account when determining the frequency distribution. The default value is false.

•

frequencies = list or Vector of nonnegative values


Specifies frequencies to be used to generate a frequency response. The list or Vector must be sorted, from smallest to largest. The units are determined by the hertz option.


Specifies the unit of frequency. If this value is set to true, the unit of frequency is Hertz; otherwise, it is radians per second. The default value is assigned by DynamicSystems[SystemOptions].

•

legend = list or element


Specifies the legend for the plot. A list specifies a legend entry for each subsystem. The elements in the list correspond to the Matrix of subsystems taken in Fortran order. An element can be used for a onebyone Matrix of subsystems. The default is no legend.


Specifies the frequency scale. If this value is set to $\mathrm{true}$, the scale is linear; otherwise, by default, the scale is logarithmic.

•

numpoints = nonnegative integer


Specifies the number of points. The default is 100.

•

output = plot, data, or list of same


Specifies the output of PhasePlot. The name plot returns the plot structure. The name data returns the data. A list of those names returns a corresponding list of plots and data. The default is plot.


The data is returned as a Matrix for a single selected subsystem and as a list of Matrices for multiple selected subsystems. Each Matrix has two columns: the first is the horizontal component and the second is the vertical component.

•

parameters = set(name = complexcons) or list(name = complexcons)


Specifies numeric values for parameters in sys. These values override those specified by the parameters field of the system object, which in turn override the settings in in SystemOptions(parameters). The numeric value on the righthand side of each equation is substituted for the name on the lefthand side in the expressions that define the model. No checking is done during the substitution to determine whether the substituted value is valid. For example, a complex value can be substituted for the coefficient of a polynomial. If the complex value had been originally assigned to the model at creation, a warning would be generated.


Specifies whether the phase is in radians or degrees. If $\mathrm{true}$, the phase is in radians, otherwise it is in degrees. The default value is assigned by DynamicSystems[SystemOptions].

•

range = range( realcons )


Specifies the frequency range to plot. The default setting is to compute an appropriate range based on the locations of the zeros and poles of the transfer functions of the selected subsystems. Similarly, if the righthand side of range is infinity, a maximum is computed based on the zeros and poles. The units are specified by the hertz option.

•

subsystem = [ posint, posint ] or list of same


Selects subsystems of a multiinput/multioutput system. Each selected subsystem is specified as a list of two indices: the first specifies the output and the second specifies the input. For example, $\left[1\,2\right]$ specifies the subsystem from the second input to the first output. A list of lists selects multiple subsystems. The default setting is to select all subsystems, using Fortran ordering. That is, for an m x n system, the default list of subsystems is [ [1,1], ..., [m,1], ..., [1,n], ..., [m,n] ].



Description


•

The PhasePlot command plots the phase versus frequency of the transfer function of a subsystem of sys, a System object.

•

If sys is a continuous system, its sdomain transfer function is computed and then converted to the real frequency domain using the transformation s > I*omega, where omega is the angular frequency.

•

If sys is a discrete system, its zdomain transfer function is computed and then converted to the real frequency domain using the transformation z > exp(I*omega*Ts), where omega is the angular frequency and Ts is the sample time.

•

The PhasePlot command uses the plot option axis to assign a logarithmic scale to an axis. This feature does not work with the default plot driver used in the Classic Worksheet interface. To use this feature in the Classic worksheet interface, or with commandline Maple, use $\mathrm{plotsetup}\left(\mathrm{maplet}\right)$. For details, see plot,device.



Examples


>

with( DynamicSystems ):

>

sys := TransferFunction( 1/(s10)):

>

sys := Coefficients(<<[1],[1,4],[3]>>,<<[1,2],[1,2,3],[4,2,1]>>):

>

PhasePlot(sys, color=[red, green], title="System Responses");

Plot selected subsystems. Note how the thickness and color options cycle independently. This is the command to create the plot from the Plotting Guide.
>

PhasePlot(sys, subsystem=[[1,1],[2,1],[3,1]], hertz, thickness=[1,1,2], color=[red,green]);



