VCO (with 8038?, opamps?)

[Magnus Danielson]

Hi Tuukka and the rest of you!

> I someone would have a schematics or something about VCO wich
> have at least triangle output and Voltage Control input in range 1-5V/Oct
> (can be wider too).
> 
> I thought that it might be possible to build this up some what easily with 
> this Harris 8038, but my rate on electronics is not high enough for that.
> Problem is to arrange that control voltage for the circuit using 8038.
> It's different waveform outputs would be perfect for VCO, and it's stability
> is not (I think) bothering me.
> 
> But ofcourse if somebody have better way to build this kind of circuitry
> (Exars XR2206 have been in mind but there is again this voltage control 
>  problem..).

Well, take a peak at the ASM-1 VCO Schematics (which you finds at 
http://www.it.kth.se/~e93_mda/synths/companies/stopp/ ). This is not directly
a one chip solution, but it will give you a saw-wavefore and square/PWM.
It will track way more then just 5 octaves (mine have tracked over 19-20 
octaves
or so...).

You may convert the sawwaveform into triangle with a simple circuit...

The VCO is quite simple to build even thougth it migth seem complex. There are
only a few hard parts of debugging errors.

I think this VCO is worth its part count, especially if you go for the MAT-02.

Cheers,
Magnus