[LAD] Harmonic generator and transfer function

fons at kokkinizita.net fons at kokkinizita.net
Wed Dec 1 15:11:48 UTC 2010

On Wed, Dec 01, 2010 at 05:21:09PM +0300, Andrew Gaydenko wrote:

> On Wednesday, December 01, 2010 16:33:35 fons at kokkinizita.net wrote:
> > > I'm afraid direct amplitude caculation in accorance with a0...aN will
> > > produce "too fast" signal deviation, resulting in exceeding fs/2 band.
> > 
> > Any non-linear transfer function will do this for some inputs.
> > If you have an x^N term, anything above Fs/(2*N) will alias.
> > If you want the nonlinearity without aliasing, you have to
> > upsample (by a factor N, with N = highest power of x used),
> > apply the nonlinear function, then downsample.
> Fons, thanks! It is *that* trick I needed to eliminate my doubts wrt fs/2 
> products :-) I think SRC is an approriate lib for up/down-sampling.

For the fixed ratios you need zita-resampler will probably
somewhat faster.


There are three of them, and Alleline.

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