VCO

[BJ]

Don Tillman wrote:
> 
>    Date: Tue, 19 Aug 1997 23:31:25 -0700
>    From: BJ <zzynt at algonet.se>
> 
>    Lately I have made two different VCO's for driving a wave table,
>    7bit in length.  The first using a LM331/4151 V/F IC.  this one
>    have extra nice linearity but are problematic to run at the high
>    frequency that's needed.
> 
>    The other one are the basic now familiar LM311 comparator and 3140
>    integrator.  This VCO can run at slightly higher frequency but I am
>    suspicious about the linearity of the VCO at those frequencys.
> 
> I don't know anything about the specific VCOs you are using but...
> 
> If these are sawtooth-based VCOs, they simply won't work well at high
> frequencies.  You'll surely want a triangle-based VCO.
> 
>   -- Don

Yes they are saw based VCo's, and thats because it's so difficult
to get a matched PNP pair to a resonable cost to drive a Triangel based
VCO.

BJ