# step

Step response plot of dynamic system; step response data

## Syntax

## Description

### Step Response Plots

`step(`

plots the response of a dynamic system model to a step input of
unit amplitude. The model `sys`

)`sys`

can be continuous- or discrete-time,
and SISO or MIMO. For MIMO systems, the plot displays the step responses for each I/O
channel. `step`

automatically determines the time steps and duration of
the simulation based on the system dynamics.

`step(___,`

specifies
additional options for computing the step response, such as the step amplitude or input
offset. Use `config`

)`RespConfig`

to create the option set `config`

. You
can use `config`

with any of the previous input-argument and
output-argument combinations.

### Step Response Data

`[___] = step(___,`

specifies additional options for computing the step response, such as the step amplitude
or input offset. Use `config`

)`RespConfig`

to create the option set `config`

. You
can use `config`

with any of the previous input-argument and
output-argument combinations.

## Examples

## Input Arguments

## Output Arguments

## Tips

## Algorithms

To obtain samples of continuous-time models without internal delays,
`step`

converts such models to state-space models and discretizes them
using a zero-order hold on the inputs. `step`

chooses the sampling time for
this discretization automatically based on the system dynamics, except when you supply the
input time vector `t`

in the form `t = T0:dt:Tf`

. In that
case, `step`

uses `dt`

as the sampling time. The resulting
simulation time steps `tOut`

are equisampled with spacing
`dt`

.

For systems with internal delays, Control System Toolbox™ software uses variable step solvers. As a result, the time steps
`tOut`

are not equisampled.

## References

[1] L.F. Shampine and P. Gahinet, "Delay-differential-algebraic
equations in control theory," *Applied Numerical Mathematics*, Vol. 56,
Issues 3–4, pp. 574–588.

## Version History

**Introduced before R2006a**

## See Also

### Functions

`impulse`

|`RespConfig`

|`initial`

(Control System Toolbox) |`lsim`

|`stepplot`

### Apps

- Linear System Analyzer (Control System Toolbox)