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# ellip

Elliptic filter using specification object

## Syntax

hd = design(d,'ellip')
hd = design(d,'ellip',designoption,value,designoption,...
value,...)

## Description

hd = design(d,'ellip') designs an elliptical IIR digital filter using the specifications supplied in the object h.

hd = design(d,'ellip',designoption,value,designoption,...
value,...)
returns an elliptical or Cauer FIR filter where you specify design options as input arguments.

To determine the available design options, use designopts with the specification object and the design method as input arguments as shown.

`designopts(d,'method')`

For complete help about using ellip, refer to the command line help system. For example, to get specific information about using ellip with d, the specification object, enter the following at the MATLAB prompt.

`help(d,'ellip')`

## Examples

These examples demonstrate how to use ellip to design filters based on filter specification objects.

### Example 1

Construct the default bandpass filter specification object and design an elliptic filter.

```d = fdesign.bandpass;
hd = design(d,'ellip','matchexactly','both');```

### Example 2

Construct a lowpass object with order, passband-edge frequency, stopband-edge frequency, and passband ripple specifications, and then design an elliptic filter.

```d = fdesign.lowpass('n,fp,fst,ap',6,20,25,.8,80);
design(d,'ellip'); % Starts FVtool to display the filter.```

### Example 3

Construct a lowpass object with filter order, passband edge frequency, passband ripple, and stopband attenuation specifications, and then design an elliptic filter.

```d = fdesign.lowpass('n,fp,ap,ast',6,20,.8,60,80);
design(d,'ellip'); % Starts FVTool to display the filter.```