piclist 2000\05\23\160143a >
Thread: [EE] Phase locking DRO's OCXOs
picon face BY : Robert Rolf email (remove spam text)

> >That is one option we are exploring. There is a nice design
> >(PIC based) that Brook Shera has put together to use the 1 PPS out of a
> I made it (with small modification - Lattice PLD chip instead the LSI
> logic) and it works really good. I am using it as a master timebase
> reference for my various instruments.

Huh? The QST article I'm working from doesn't have a PLD (that I can
recall). It used discreet logic for everything. Is there a more
current design that I've obviously not seen? It would make sense to
use a PLD to simplify the construction (lots of dividers at al).

> But oscillator is a real problem. I tried couple of TCXOs and results was
> not good. Finally I bought the OCXO (expensive) and results are much much
> better.
> Currently, I am trying to make my own OCXO as a hobby project.

Then I guess we had better have an off-line chat.

> >The plan is to come up with methods that amateurs can duplicate for
> >themselves without too much effort. Things like building your own
> >TCXO's with a 12Cxxx part as controller.
> Look at http://www.karlquist.com  - Rick Karlquist was developping OCXOs for

EXCELLENT collection of info. Thanks. Knowing that we could borrow a
really good reference I was leaving that part for later.

> Hewlett-Packard and he knows a lot about the whole problem. On his pages,
> there is a very nice and detailed design of ultra high precision OCXO
> (which I am trying to duplicate at home). The whole design is patented, but
> I got the permission from Rick to use the design for non-profit projects
> (because HP is not currently actively using this patent in any design).

Really? With 9 other 'inventors' how can just ONE give permission to
use the patent?

> The whole oscillator is a bit complex to make (you need lathe and mill),

Not a problem for us, or serious amateurs I would think.

> but the result should be perfect. BTW, he is using PIC16C73 for the PID
> control of the oven temperature.

Yes, that keeps us ON topic I guess.


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