# feedback

Feedback connection of multiple models.

## Syntax

* sys = feedback(sys1, sys2)
* sys = feedback(sys1, sys2, sign)

## Input argument

* sys1, sys2 - LTI models: Systems to connect in a feedback loop.
* sign - Type of feedback: -1 (default) or +1.

## Output argument

* sys - Closed-loop system.

## Description

sys = feedback(sys1, sys2) generates a model object, sys, representing the negative feedback interconnection of the model objects sys1 and sys2.

## Example

```matlab
G = tf([2 5 1], [1 2 3]);
C = tf([5, 10], [1, 10]);
sys = feedback(G, C, +1)
```

## See also

[cloop](cloop), [append](append), [ssselect](ssselect).

## History

| Version | Description     |
| ------- | --------------- |
| 1.0.0   | initial version |

## Author

Allan CORNET
