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Fernando

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Typical Audio, CD quality Anti aliasing filter
Nov 05^th, 2010, 4:15pm

Hi all,

I am trying to setup a simulink model of a typical anti-aliasing filter used in audio, CD quality (ie 44Khz sampling rate).

Does anybody know of any reference that provides the coefficients of a typical Laplace transfer function that implements such a filter (including order, type (Bessel, Butterworth, etc)?; I am ok if I get the coefficients for the normalized angular frequency instead.

I want to stress that I am not after an analog filter primer but rather about the Laplace coefficients of an analog filter as close as those used in practice.

Thank you in advance.

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ACWWong

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Oxford, UK

Re: Typical Audio, CD quality Anti aliasing filter
Reply #1 - Nov 6^th, 2010, 12:37pm

since you already using simulink, matlab gives you the transfer functions of butterworth, bessel cheby etc. analog filters

buttap
besselap
etc.

you can get the syntax from using help <command> in matlab.

once you have the poles and zeros you can get the coefficients of the laplace transform of transfer function by using the poly function

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buddypoor

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Bremen, Germany

Re: Typical Audio, CD quality Anti aliasing filter
Reply #2 - Nov 7^th, 2010, 2:29am

Fernando wrote on Nov 5^th, 2010, 4:15pm:

Hi all,

I am trying to setup a simulink model of a typical anti-aliasing filter used in audio, CD quality (ie 44Khz sampling rate).

Does anybody know of any reference that provides the coefficients of a typical Laplace transfer function that implements such a filter (including order, type (Bessel, Butterworth, etc)?; I am ok if I get the coefficients for the normalized angular frequency instead.

I want to stress that I am not after an analog filter primer but rather about the Laplace coefficients of an analog filter as close as those used in practice.

Thank you in advance.

Fernando,
do you hear about some powerful filter design programs which are available for free in the web?

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LvW (buddypoor: In memory of the great late Buddy Rich)

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buddypoor Community Fellow Offline Posts: 529 Bremen, Germany	Re: Typical Audio, CD quality Anti aliasing filter Reply #3 - Nov 7^th, 2010, 9:35am Mote than that, I direct your attention to AN699 from Microchip.
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