dpoly (Simulink Reference)

Display a transfer function on the icon of a masked subsystem.

Syntax

dpoly(num, den)
dpoly(num, den, 'character')

Description

dpoly(num, den) displays the transfer function whose numerator is num and denominator is den.

poly(num, den, 'character') allows you to specify the name of the transfer function's independent variable. The default is s.

When the icon is drawn, the initialization commands are executed and the resulting equation is drawn on the icon:

To display a continuous transfer function in descending powers of s, enter

```
dpoly(num, den)
```

For example, for num = [0 0 1]; and den = [1 2 1]; the icon looks like this:

To display a discrete transfer function in descending powers of z, enter

```
dpoly(num, den, 'z')
```

For example, for num = [0 0 1]; and den = [1 2 1]; the icon looks like this:

To display a discrete transfer function in ascending powers of 1/z, enter

```
dpoly(num, den, 'z-')
```

For example, for num and den as defined previously, the icon looks like this:

To display a zero-pole gain transfer function, enter

```
droots(z, p, k)
```

For example, the preceding command creates this icon for these values:
- ```
z = []; p = [-1 -1]; k = 1;
```
You can add a fourth argument ('z' or 'z-') to express the equation in terms of z or 1/z.

If the parameters are not defined or have no values when you create the icon, Simulink displays three question marks (? ? ?) in the icon. When the parameter values are entered in the mask dialog box, Simulink evaluates the transfer function and displays the resulting equation in the icon.

See Also

```
disp, port_label, text
```

disp fprintf