Odp: [sdiy] triangle to sine converter

[Roman]

Hi,
I start to like the idea. It's easy to imagine even 2 integrators
following trangle VCO on the same module, tuned exactly like
the VCO. It should give more or less stable amplitude across
whole tuning range.
SSM2164 - one VCA as VCO core, 2 as tunable integrators
or actually a filter, all driven with the same CV.
anyone to breadbord this? :)
OTOH the sine might be just too perfect then...

Roman

----- Original Message -----
From: Seb Francis
To: synth diy
Sent: Friday, October 11, 2002 2:56 AM
Subject: [sdiy] triangle to sine converter


woops, here's the mail again including gif ..
--
Ok, so it isn't a perfect sine .. but it's very close, and I bet it would sound
close (maybe even a little "richer" than a pure sine)
blue line is "dy" (triangle wave)
red line is pseudo-sine whose gradient is "dy"
green line is real sine, scaled to match
Now, my maths is coming back to me a little, and I seem to remember that the
gradient of a sine is actually a cosine (which is an out of phase
sine).  So if you took the pseudo-sine wave and stuck it through a buffer,
another resistor, current-mirror, and capacitor then you would get an
even purer sine wave.