[sdiy] VCO Tuning goals

[cheater cheater]

No, about a saw core vco. I don't see a way this could work with a
triangle core.

The idea is that one saw comes from cap1, the next one from cap2, and
then cap1 again, and so on.

So, alternating the caps.



On Wed, Oct 7, 2009 at 2:39 AM, Ian Fritz <ijfritz at comcast.net> wrote:
> At 06:46 PM 10/6/2009, Aaron Lanterman wrote:
>>
>> The EML state varible filter uses and interesting "differential
>> integrator" that has two capacitors. It's not "switched," but it may
>> provide inspiration.
>
> Or see my switched differential integrator oscillator in EN #111 (1980).  I
> developed this further a few years ago, and even had it on my website for
> many years.  To match the caps I made each one from a parallel pair, so it
> was easy to find matched pairs.
>
> Ian

Great stuff Ian! Will need to check it out...

D.

On Wed, Oct 7, 2009 at 1:15 AM, David G. Dixon <dixon at interchange.ubc.ca> wrote:
>> Can't you get around the cap discharge time by using two capacitors
>> and switching between them? One is getting discharged while the other
>> one is loading?
>
> I presume you're talking about a triangle-core VCO?  That's a very
> interesting idea.  However, it would require a very (VERY) careful trim of
> the resistors feeding each cap to ensure triangle symmetry, and also two
> very well matched JFETs (matched for on-resistance).  Still, interesting
> idea (the "push-me-pull-you VCO"!)
>
>