[time-nuts] is there a cheap and simple way to measure OCXOs?

[Chris Albertson]

On Tue, Jun 5, 2012 at 3:18 AM, Attila Kinali <attila at kinali.ch> wrote:

> On Wed, 30 May 2012 15:11:03 +0200
> Attila Kinali <attila at kinali.ch> wrote:
>
>
> > I recently bought some Oscilloquartz 8663 from ebay and am now wondering
> > how to check whether they are working correctly or whether they are
> > out of specs.
> >
> > Unfortunately, although i have a reasonable park of measurement
> instruments,
> > none of them are in the precision range that i'd need to characterize
> > the 8663's.
>
>
> thanks everyone for the answers! I did dig a little bit trough the avilable
> devices (ie those that do not cost me an arm and a leg to buy) and came
> to the conclusion that i have to reformulate my requirements.
>
> I think, the most important thing for me at the moment is to verify that
> i do not have any defect devices. Defect in the sense of something other
> than "does not output any signal" (these are trivial to detect).
>
> And here i'm stuck again. What are likely defects of an OCXO? And how would
> i detect them?
>
>
A working oven heater will pull a bit of current when you first turn it on
as it heats the oven up from room temperature then the current goes down.
I think if you see this kind of current v. time plot the oven is working.
I don't know how long it takes but certainly after 20 minutes it should be
in steady state mode.   Generally the heater would be on solid at first
then cycles on it's control loop.

Next  connect a pot to the frequency control and verify the frequency
tracks the voltage.  Easy way is to but two on a stop and look at the
relative phase.  You can't know it it is dead-on 10MHz but you can see that
the adjustment works.

A cheap test tool is a mixer.  You can build a double balanced diode ring
mixer for about $5

Chris Albertson
Redondo Beach, California