digital control of analog component question...

[The Proteus]

Gents,

	This opens up a whole new topic of discussion on how to interface
the D/A to the analogue circuit. I was grilled on a question about the
difference between VCO's and DCO's in an interview for my current
employer, and the only difference I could think of is that a DCO is a VCO
with D/A on all the CV inputs. Then it got me to thinking, how many
current output DACs there are out there, and even some of them having
logarithmic current output. Why have an I->V converter on the output of a
DAC, then go trhough another V->I converter on the input of the VCO? Since
most VCO's I've worked with and built have an OTA current-control gain
cell at its core, this could prove to be an advantage both in noise and
parts cost. Anyone care to followup on this thread? Any other differences
between a VCO and a DCO that people have noted over the years?

The Proteus - Morphing the convergence of technology and passion.
-- Musician - Producer - Engineer  -  UNIX Admin Extrordinaire --
"...the best workaround for a bug in a UNIX utility is to install 
 the GNU version" - Kragen Sitaker

On Wed, 12 Jan 2000, Magnus Danielson wrote:

> 
> Yes, this is one of many popular ways of doing it.
> 
> Then there are more ways to control curcuits by digital meants, like CMOS
> switches and such. There are also all kind of hybrid solutions by which the
> frequency generation is done digitally but waveshaping is done by analog etc.
> 
> Cheers,
> Magnus
>