[sdiy] CMOS Saw to Triangle Waveshaper (corrected URL)

[René Schmitz]

At 07:49 04.11.01, Scott Gravenhorst wrote:
>Heh heh, you guys!
>
>I'm getting there.  I did think about that, but I drew
>it with opamps before I thought of it.  In fact, the 
>LFO is the only part not yet built.  I know I can make
>a sawtooth this way, but tri ... ?  With 3 inverter gates?
>Hmm.  The integrator is easy I think.  The schmitt trigger?
>2 gates setup as linear inverters connected together makes
>a noninverting gain stage, then some positive feedback
>in that system?  I'll play around, perhaps today.  I
>*am* trying to keep this as much CMOS as possible, so that
>would be a good use of those gates.

Look at the VCO core. There is such a schmitt already. Triangle would 
mean to change the discharge diode to a resistor, and ommit the current sink.
(And also ommit the Franco resistor and the Diode at the cap.)
However, the generated triangle would sit on Ub/2, and the CCW-end of
frequency 
pot in the LFO would need to be referenced to that voltage instead 
of GND. Unless one fiddles with the supplies. One could power them from 
+5/-5V or so to make that easier.

>And then there's the 2 analog switches and the flipflop...
>Actually, the flipflip's clock has a shcmitt trigger input.
>I wonder if there's a way to use the JK in an LFO somehow.  

I'd rather make a dual VCO and use up the other half of the waveshaper ICs.

Cheers,
 René

-- 
uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159