d2dOptions

Create option set for discrete-time resampling

Syntax

opts = d2dOptions opts = d2dOptions('OptionName', OptionValue)

Description

opts = d2dOptions returns the default options for d2d.

opts = d2dOptions('OptionName', OptionValue) accepts one or more comma-separated name-value pairs that specify options for the d2d command. Specify OptionName inside single quotes.

This table summarizes the options that the d2d command supports.

Input Arguments

Name-Value Arguments

Method

Discretization method, specified as one of the following values:

`'zoh'`	Zero-order hold, where `d2d` assumes that the control inputs are piecewise constant over the sample time `Ts`.
`'tustin'`	Bilinear (Tustin) approximation. By default, `d2d` resamples with no prewarp. To include prewarp, use the `PrewarpFrequency` option.

For information about the algorithms for each d2d conversion method, see Continuous-Discrete Conversion Methods.

Default: 'zoh'

PrewarpFrequency

Prewarp frequency for 'tustin' method, specified in rad/TimeUnit, where TimeUnit is the time units, specified in the TimeUnit property, of the resampled system. Takes positive scalar values. The prewarp frequency must be smaller than the Nyquist frequency before and after resampling. A value of 0 corresponds to the standard 'tustin' method without prewarp.

Default: 0

Examples

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Specify Method for Resampling a Discrete-Time Model

This example uses:

Control System Toolbox Control System Toolbox

Open Live Script

Create the following discrete-time transfer function with sample time 0.1 seconds.

$H (z) = \frac{z + 1}{z^{2} + z + 1}$

h1 = tf([1 1],[1 1 1],0.1);

Specify the discretization method as bilinear Tustin method with a prewarping frequency of 20 rad/seconds.

opts = d2dOptions('Method','tustin','PrewarpFrequency',20);

Resample the discrete-time model using the specified options.

h2 = d2d(h1,0.05,opts);

You can use the option set opts to resample additional models using the same options.

Version History

Introduced in R2012a