Fast-fourrier transformation

Matt Haines haines at apc.net
Sun Aug 18 01:22:42 CEST 1996


>Hi!
>
>I'm working with a friend on a VCO, and I have coded a little
>program in turbo pascal, that allows you to draw a wave,
>and then send all 256 steps thru the parallel port, to the VCO.
>
>I will need a way to find out the base frequency of this 256step wave,
>in order to scale it (by delays between steps) to the correct
>frequency for each note ... could you PLEASE (we're both in
>high school, and we don't know anything about this kind
>of advanced mathematics) help us by telling us how we could calculate
>the base frequency?
>
>someone told us this is a fast-fourrier analysis, but we don't
>know how to do that either ... please help!
>

The frequency of this waveform is determined by how fast you're playing it
back. There is no inherent frequency to a set of data.

If your playback rate happens to be 44.1kHz, then the frequency of this
waveform (assuming one wavecycle takes up all 256 steps) would be 172.27 Hz
(rounded). So what's clocking this waveform? That'll determine the
frequency.

.       .       .       .       .       .       .       .       .
    .       .       .       .       .       .       .       .
.       .       .       .       .       .       .       .       .
Matt Haines  haines at apc.net         .       .       .       .
control-X:to:abort:transmission .       .       .       .       .
    .       .       .       .       .       .       .       .
.       .       .       .       .       .       .       .       .
    .       .       .       .       .       .       .       .
Analog Purist Wacko





More information about the Synth-diy mailing list