# dstep (MathScript RT Module Function)

LabVIEW 2012 MathScript RT Module Help

Edition Date: June 2012

Part Number: 373123C-01

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Owning Class: modeling and prediction

Requires: MathScript RT Module

## Syntax

dstep(num, den, tf)

dstep(A, B, C, D, ui)

dstep(A, B, C, D, ui, tf)

[Y, X] = dstep(num, den, tf)

[Y, X] = dstep(A, B, C, D, ui)

[Y, X] = dstep(A, B, C, D, ui, tf)

[Y, X, T] = dstep(num, den, tf)

[Y, X, T] = dstep(A, B, C, D, ui)

[Y, X, T] = dstep(A, B, C, D, ui, tf)

## Description

Computes the step response of the discrete system model. You can use this function to return the step response of the model outputs. This function assumes the initial states of the model are zeros. If you do not request an output, this function plots the step response in the current plot window.

Examples

## Inputs

Name Description
num Specifies the numerator polynomial function of a transfer function equation. num is a real vector.
den Specifies the denominator polynomial function of a transfer function equation. den is a real vector.
A Specifies an n-by-n state matrix, where n is the number of model states. A is a real matrix.
B Specifies an m-by-n input matrix, where m is the number of model inputs. B is a real matrix.
C Specifies an r-by-n output matrix, where r is the number of model outputs. C is a real matrix.
D Specifies an r-by-m direct transmission matrix. D is a real matrix.
ui Specifies the index number of the model. The default is 1.
tf Specifies the final time for the impulse response.

## Outputs

Name Description
Y Returns the time response of the outputs of the model due to the step input. Y is a real matrix.
X Returns the time response of the states of the model due to the step input. X is a real matrix.
T Returns the uniformly spaced time vector this function uses to calculate the step response and the state trajectories. T is a real vector.

## Details

The following table lists the support characteristics of this function.

 Supported in the LabVIEW Run-Time Engine Yes (if you request output) Supported on RT targets Yes (if you request output) Suitable for bounded execution times on RT Not characterized

## Examples

num = 1;
den = [1, 1];
dstep(num, den, 16)

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