ODP: Harmonix content formula and FT, Analog stylee

[Roman Sowa]

To all and especially to:

Martin tempted with analog FT idea:
It just came into my mind - since FFT butterfly calculations are only
one multiply with constant coefficient and adding and substracting
then it can be made with opamps, or any other amplifiers. It is complex
multiply, but it only increases the number of opamps.
So to get Instant spectrum analysis all we need is analog delay line
with taps feeding first column of butterflies, and lots of opamps.
Unless I'm mistaken again.

Paul who made a wobbulator:
I'm not exactly sure how you want to use it in morphing, but those kind
of analyzers are known for years (as also Maciej mentioned).
An Idea: the output of such analyzer, which is some repetitive signal
could be fed into a filter of some kind, oscilating and sweeping, and then
maybe some other waveshapers. This would cause substantial change
in the spectrum. Reversing the analyze process with this spectrum as
an input would produce some interesting results.
But anyhow dominating frequency in ovwerall output will be sweep
frequency of the analyzer.
bad Idea and seemed to be so cool at first :-(

Paul - part 2:
you wrote:
'to have a stage where by you have a frequency select pot and another 
for level you could at this point as the bandpassfilter got swept though it 
and adjust the level of this frequency.. again the frequency select could be

voltage controlled'
so you want resonators right?, like in PS3xxx(?) synths but having 8
formants?
this would be so great, especially when you could controll them using
four joysticks or something like that

Maciej - DCT
Thanks for explaining that. I always wondered what happens to imaginary part
but never took the time to find out. So we could do DFT - sines and cosines,
multipliers, integrators...
If you teach FT, so I guess (everybody agreed?) from now you'll be
Fourier guru :-)  So what do you think about my idea of 100s of opamps in
FFT butterflies?

Roman