tri 2 saw modulation

[List, Chris]

	> Here's another aproach:  Start with a sawtooth VCO and build a
circuit
	>  to warp the symmetry of that.  

	<VCA and control voltage techniques omitted>

	Another option;
	Simply create a saw-VCO. Create a tri converter using a
transistor and resistor. Make an exponential  VC-Crossfade between the
two outputs using the technique in the data sheet for the SSM2024 (see
the Analog Devices www page), or a linear x-fade using two 3080's such
as the one in the wave shaper described in both electronotes PCC and the
Barry Klein book (I forget the name of the circuit but it x-fades
between a FWR signal and a normal signal).

	Both of these are circuits that can be built with 5 chips or
less.

	Of course you can build this VC-xfade into the VCO, but you
might want to make it a separate module :).

	The coolest option (if you want to get fancy) would be to build
some kind of trapezoid-function x-fade that would take 4 inputs (saw,
sine, square, tri) and cross-fade between each as the input voltage goes
from 0 to +6v, so that 0v would be saw, 1v would be saw + sine, 2v would
be sine, 3v would be sine + square, etc, etc... The tricky part is
creating the CVs for the 4 VCAs. Juergen accomplished this rather
elegantly using transistor tricks with his "Interpolating Scanner"
design (a great design, BTW). 

	- CList