[time-nuts] Older Lucent GPSDO and Rubidium combo

[Paul Cloud]

Well I suppose that my use of the word "spec" was incorrect the quote
is listed below.

"OM redundancy The Oscillator Module provides a highly stable timing reference
capable of being disciplined from an external source, such as the GPS
receiver or network clock. Two versions are available: Rubidium based
(OMR), which is capable of running for 24 hrs without an external
reference (flywheeling), and Quartz Crystal based (OMQ), which can
flywheel for eight hours. The OMR serves as a primary timing
reference where high long term accuracy is required. The OMQ can be
used as a primary source, where long term drift accuracies are more
relaxed or as a secondary (back-up), to be used upon the primary’s
failure. The OMR may also be used as secondary if desired, in
applications where low cost is not a requirement."

I should also state that this is not from actual documentation for the
unit that I have. But, it is actual documentation for a system later
by some 3 years.

Thanks and 73, Paul



On Sun, Dec 12, 2010 at 11:00 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
>
>> Are you under the impression that the Rb is disciplined also? I had thought
>> that the GPSDO side was disciplined and the Rb was only for holdover, they
>> seem to call it fly-wheeling. They spec 8 hour holdover for the GPSDO and 24
>> hour holdover for the Rb in the limited info I've been able to snag. I'm
>> still digging for more info.
>
> Holdover is more than just a single number.
>
> I'd expect something like:
>  The PPS will be within X microseconds for Y hours.
>
> It might be that there are two sets of specs, one for a crystal and another
> for a Rb option.  I'd expect the Rb option to have smaller X or longer Y.
>
>
> Most Rb units have an adjustment (screwdriver or voltage) to correct for the
> local magnetic field.  If you have that sort of adjustment voltage, you can
> easily turn it into a GPSDO.
>
>
> --
> These are my opinions, not necessarily my employer's.  I hate spam.
>
>
>
>
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