[sdiy] Squarewave

["Rönnberg, Niklas"]

Dear DIY'ers,

It's been a while since my voice was heard here... But I've been
reading, reading and reading and trying to learn.
Anyway I have a question regarding a simple square wave generator:
http://www.itn.liu.se/~nikro/diy/square.gif

I want to control the frequency and I guess that one way to do this is
to put a pot in series with the resistor. But actually I would like to
control it with a control voltage...

I made a phaser (ETI447) some weeks ago:
http://www.itn.liu.se/~nikro/diy/phaser/

And it uses a 4049 as 6 variable resistors, with both pin 1 (VDD) and 8
(VSS) connected to ground (or VREF). A triangle wave is connected to the
inputs and the outputs go to the +in on the opamps. In series there is a
resistor from +in to VREF. This makes the resistance between +in and
ground (or VREF) varies between 100K and some few K.

Is it possible to use this solution to control the frequency of the
square wave? It looks hard to me, but maybe you can see the light... :-)

Best regards

Niklas