FM of Tri-Square VCO

[A.S.P.]

On 6 Sep 1996, Christopher List wrote:

> Howdy DIYers - 
> 
> It was mentioned a while back that the Tri-Square VCO (of 
> Electronotes/Elctronic Music Circuits) couldn't do "through zero FM". I have a 
> vague notion of what this limitation implies - just from looking at the FM'ed 
> waveforms on a scope, but I'm 100% sure. 
> 
> 1. Could someone describe this limitation (or rather, this capablility)?
> 2. Does anyone know if it would be possible to modify the circuit so that it 
> could do through-zero FM? 
> 3. How? 

Wouldn't that be the through zero VCO in Option 4? (I'm assuming you're 
asking about the Option 3 tri/square VCO.)  Note that the two have the 
same output circuitry.


R.