[PD] help with rfft~

[Stefan Turner]

--- Mathieu Bouchard <matju at artengine.ca> wrote:

> On Tue, 29 Nov 2005, Stefan Turner wrote:
> 
> > I think the standard way of convolution - or at
> least the one I use -
> > which gives ok results, is to have one 'carrier'
> signal, which is
> > filtered by the 'modulator' signal. (I think
> that's what they're
> > called.) Basically, first get the magnitude of the
> modulator:
> > sqrt(real^2 + imag^2). Then:
> > output real = carrier real * modulator magnitude
> > output imag = carrier imag * modulator magnitude
> 
> This is not a plain convolution by the modulator
> signal, though it's
> close. It's a convolution by the phase-removed
> modulator signal, because
> all phase information is removed. A general
> convolution allows for phase
> shifts.
<snip>
> A general convolution uses complex multiplications,
> one of which requires
> four real multiplications in cartesian repr, one
> real multiplication in
> polar repr, and no multiplication in log repr.

Yes, thanks for pointing this out. Apologies for this.
I have since posted the correct equations, for
cartesian.

Stefan Turner


	
	
		
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