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Modeling >> Behavioral Models >> Typical Audio, CD quality Anti aliasing filter
https://designers-guide.org/forum/YaBB.pl?num=1288998939

Message started by Fernando on Nov 5^th, 2010, 4:15pm

Title: Typical Audio, CD quality Anti aliasing filter
Post by Fernando 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.

Title: Re: Typical Audio, CD quality Anti aliasing filter
Post by ACWWong on 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

Title: Re: Typical Audio, CD quality Anti aliasing filter
Post by buddypoor on Nov 7^th, 2010, 2:29am

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

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

Title: Re: Typical Audio, CD quality Anti aliasing filter
Post by buddypoor on Nov 7^th, 2010, 9:35am

Mote than that, I direct your attention to AN699 from Microchip.