Yeah, I thought a lot about doing it all in some microcontroller, with FFTs
and Goertzel et al, but I'm trying to do it all in analog electronics.

On Wed, Dec 2, 2009 at 6:05 PM, Marcel Birthelmer
<marcelb.lists@gmail.com>wrote:

> On Wed, Dec 2, 2009 at 9:01 PM, andrew kelley <leetslacker@gmail.com>
> wrote:
> > Use a discrete fourier transform.
> >
> > http://www.dspguide.com
> > http://www.dattalo.com/technical/theory/dtmf.html
> > http://en.wikipedia.org/wiki/Discrete_Fourier_transform
> > http://en.wikipedia.org/wiki/Discrete-time_Fourier_transform
> >
> > Andrew
>
> If you're only looking for a single frequency, you don't have to do
> the full spectrum DFT... you can just calculate the frequency
> components in question.
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