[chuck-users] heads up for

Kassen signal.automatique at gmail.com
Tue Sep 12 07:13:36 EDT 2006

On 9/12/06, Ge Wang <gewang at cs.princeton.edu> wrote:

This is a 2nd order butterworth.  In the future, if we want our
> 24db/oct filter, it might be cool to chuck 4 to:
>      .order (filter order)
> Furthermore, there could be something to control the type:
>      .type (butter, cheb1, cheb2, ellip, more)

I realy like that way of looking at things. It should also work well with
going from a general large-scope structure to details and refining in the
programing process. This a good idea IMHO, way better then LPF12, LPF24,
LPFWasp ;¬) and so on.

(Of course, it's worth remembering that we can already construct any of
> these higher order filter using building blocks such as BiQuad's and
> PoleZero's.)

Theoretically, yes. I for one need way more reading/homework/time to let it
sink in to be able to do that....

Now, I am not sure if this is the right factoring.  But organizing it
> by function (low, high, etc.) seems slightly better than a monolithic
> FlexFilter type...

I agree.

> If we want to go all out, someone could implement a chuck library for
> filter design, like the lovely matlab functions such as
>      .buttord (great name; specs in, minimum butterworth order required
> out)
> as well as analog prototyping functions and bilinear transform??  It's
> probably pointless to try to duplicate matlab in any significant way,
> but the filter package is really fun and can be good for teaching in an
> audio driven manner.  That would give us many different ways to
> approach filter and friends.
> now I am talking crazy...  must be dreaming...

No, this would be great!

I've been thinking that if we have realy open-ended filters as well as the
posibility to do loads of things with time then it might make sense to at
some stage see how close we could get to EMU style morphing filters and
similar sorts of things. A library/tookit type thingy with a "how to get
started" sort of tutorial would be most welome here. I realy like how a
function-call can be used to set a filter by coeficients but how to
construct such a function (math wise) is a big question to me.

I like where this is going.

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