Marcel Birthelmer wrote:
> - filter() looks something like 1/128 * getsamp(t) + 1/128 * getsamp(t
> - sampdt) ?

No, not really.  Each filter pole uses the standard algorithm of

  FILT <-- FILT + FF(NEW - FILT)

Where NEW is the input value being added to the filter, FILT is the filter
being updated, and FF is the filter fraction.  My filter used two such
poles, each with a filter fraction of 1/128.

> Or is it an IIR filter?

Yes.

> - What is the trunc() bit?

It converts from floating point to integer by truncating the fraction part.
For example, trunc(3.14) = 3.

> A peculiarity of the arcane language (I'm
> guessing fortran) you're using?

It's a variant of Pascal.  I was hoping the algorithm would be clear enough
even if the syntax details weren't familiar.


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