On 20 Apr 2004 at 8:43, Richard.Prosser@POWERWARE.COM wrote:

> I don't have a tutorial, but may be able to assist with sample code. (and
> other help if required)

        Thanks Richard, I appreciated that.

        Have read lots of info about FFT, but still don't get it right.
        I found an excelent description of the Goertzel algorithm here:

        http://www.embedded.com/story/OEG20020819S0057

        Based on that info, I wrote a program to do it using an ATmega8.
        It worked nicely detecting DTMF tones! And it is very versatile
and easy to tweak up!
        The assembler program used 10bit samples scaled to 12bit and the
coefficients scaled to 14bits. All the multiplys are 16bit.

        Well, what I'm trying to design is an 8 or 16 tone AFSK modem.
        Based on what I have read, it seems Goertzel is just one form
of calculating the FFT. But will it give me the best results?

        Do you know of some page describing the FFT process like that
one on the Goertzel algorithm?

        Thanks.
        Mark Jordan

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