ODP: AW: Harmonix content formula

[Roman Sowa]

convolution - I agree, but look at it this way:
frequency bin coefficient is an integral taken over whole sine period
of multiplied input and sine (or cos). Lets assume we calculate only
those coefs derived from cosine waves. So instead of mentioned
envelope followers (shortcut thinking mistake) integrators would be
required, which outputs are sampled at the end of fundamental cycle
and then the integrators are reset.

You say, that I see FT like filtering with sine impulse response filter...
Convolution with sine IS filtering with sine impulse response filter.

Roman

> -----Oryginalna wiadomość-----
> Od:	Martin Czech [SMTP:martin.czech at intermetall.de]
> Wysłano:	9 czerwca 1999 13:09
> Do:	synth-diy at mailhost.bpa.nl; Roman.Sowa at WizjaTV.pl
> Temat:	Re: ODP: AW: Harmonix content formula
> 
> > Now I have dangerously silly idea - DCT in analog hardware:
> > (Discrete Cosine Transform - simplifed version of Discrete Fourier
> > Transform)
> > say, 32 sine oscilators of harmonic frequencies (or not harmonic - why
> stick
> > to the original?), 32 multipliers (ringmods) multiplying input signal
> with
> > each of
> > 32 sine oscs (or one muxed), 32 envelope followers and we have harmonic
> > content output.
> > 
> ???
> 
> sorry
> 
> My understanding is that FT looks like convolution with sine waves,
> not multiplying. That would be too easy.
> 
> If you see it this way, FT is like filtering and the filter impulse
> response is a sin/cos wave.
> 
> m.c.