Hey,
I'm playing around with the theoretics of digital filters trying to implement a Chebyshev-filter. Yet I don't know how and why to use chebyshev-stuff (..eh stuv..). So by the way if someone knows a neat site with an overview of filters and the how and why, please share it with us.

Anyways as a first step I went to wikipedia and tried to just copy the formulae for the (biquad-) coefficients... but the result doesn't look like a chebyshev-filter (at least it looks like a lp..)
So could someone with the needed knowledge have a look at the digital implementation (="Digitale Realisierung") and tell me if that's correct?! Oh and it's in german ... (little text)
...the alpha_i's and beta_i's are supposed to be the coefficients to be calculated in the end...

http://de.wikipedia.org/wiki/Tschebyscheff-Filter#Digitale_Realisierung

Bye
Flipp

There already are Chebyshev objects in pd-extended (iemlib).
For example [lp10_cheb~].
Hope this helps, even if you want to recreate one...

Oh thanks, I didn't know that.
Shurely that helps, at least as a working reference.. (as long as that code wasn't taken from the wiki as well...;) )

...argh it uses the [filter~] object and I had some odd problems with it before, but the frequency-response was never a problem...