# Wolfram Language & System 11.0 (2016)|Legacy Documentation

This is documentation for an earlier version of the Wolfram Language.
BUILT-IN WOLFRAM LANGUAGE SYMBOL

# EllipticFilterModel

designs a lowpass elliptic filter of order n.

EllipticFilterModel[{n,ωc}]
uses the cutoff frequency ωc.

EllipticFilterModel[{"type",spec}]
designs an elliptic filter of the specified type "type", using the spec.

EllipticFilterModel[{"type",spec},var]
expresses the model in terms of the variable var.

## DetailsDetails

• EllipticFilterModel returns the designed filter as a TransferFunctionModel.
• EllipticFilterModel[{n,ω}] returns a lowpass filter with attenuation of (approximately 3 dB) at frequency ω.
• uses the cutoff frequency of 1.
• Filter specification {"type",spec} can be any of the following:
•  {"Lowpass",{ωp,ωs},{ap,as}} lowpass filter using passband and stopband frequencies and attenuations {"Highpass",{ωs,ωp},{as,ap}} highpass filter {"Bandpass",{ωs1,ωp1,ωp2,ωs2},{as,ap}} bandpass filter {"Bandstop",{ωp1,ωs1,ωs2,ωp2},{ap,as}} bandstop filter
• Frequency values should be given in an ascending order.
• Values ap and as are absolute values of passband and stopband attenuations, respectively.
• Given a gain fraction , the attenuation is .

## ExamplesExamplesopen allclose all

### Basic Examples  (2)Basic Examples  (2)

A third-order elliptic filter model with cutoff frequency at :

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Bode plot of the filter:

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A lowpass elliptic filter using the full specification:

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Magnitude response of the filter showing the ideal filter characteristics:

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