# tfdata

Access transfer function model data.

## Syntax

* \[numerator, denominator] = tfdata(sys)
* \[numerator, denominator, Ts] = tfdata(sys)
* sys = tf(numerator, denominator)
* sys = tf(numerator, denominator, Ts)

## Input argument

* sys - a LTI model.

## Output argument

* numerator - polynomial coefficients: a row vector or as a cell array of row vectors.
* denominator - polynomial coefficients: a row vector or as a cell array of row vectors.
* Ts - Sampling time Ts, default: in seconds

## Description

The function tfdata(sys) retrieves the matrix data numerator, denominator from the transfer function model (LTI array) represented by sys.

If sys is initially in the form of a state-space model (LTI array), it is automatically converted to the transfer function representation before extracting the matrix data.

## Example

```matlab
numerator = 10;
denominator = [20, 33, 44];
sys = tf(numerator, denominator)
[num, den] = tfdata(sys)
```

## See also

[tf](tf).

## History

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

## Author

Allan CORNET
