[time-nuts] 5370B OCXO

paul swed paulswedb at gmail.com
Fri Mar 12 13:51:00 UTC 2010


If I understand this thread correctly.
I would speculate it was simply a business choice. 1 less part type to
manage.

On Fri, Mar 12, 2010 at 7:30 AM, Bob Camp <lists at rtty.us> wrote:

> Hi
>
> I guess the real question is what a "better" OCXO would have actually cost.
>
> If the 60111 was a test ten, get ten sort of thing (I'm guessing it was) -
> was a better part simply a test 10 get 9 issue?
>
> The claim was made that short term stability testing could be done directly
> in the aging racks. It's not real clear what the actual cost of an extended
> test / sort would have been.
>
> Bob
>
>
> On Mar 11, 2010, at 10:43 PM, John Miles wrote:
>
> > Many if not most 5370-based measurements are based on differential timing
> > between the START and STOP channels, and wouldn't benefit from a better
> 10
> > MHz reference.  If a customer did need something better, they probably
> > already had a house standard to pipe in the back... and if not, HP would
> > have been able to sell them one.  It made more sense to keep the cost
> down
> > by not including a high-end OCXO that would have gone unappreciated by
> most
> > users.
> >
> > The 5370's jitter+resolution floor doesn't allow it to reach 1E-11 at
> t=1s
> > in any event, so the -60111 wouldn't have been the limiting factor in the
> > short term.
> >
> > One valid question, though, is why they bothered to put the nicer
> > 10811-60109 OCXOs in the post-2120 series 5065A models, where its
> short-term
> > performance is hosed by tying it to the rubidium reference with a ~1 Hz
> > loop.  Those 5065As would have been OK with a -60111, at least in the
> > pre-2632 serial #s with the original integrator board.  I'd be curious to
> > know if they lowered the loop BW when they respun the integrator PCB.
> >
> > -- john, KE5FX
> >
> >
> >> -----Original Message-----
> >> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
> >> Behalf Of Bob Camp
> >> Sent: Thursday, March 11, 2010 7:11 PM
> >> To: Discussion of precise time and frequency measurement
> >> Subject: [time-nuts] 5370B OCXO
> >>
> >>
> >> Hi
> >>
> >> The OCXO in the 5370B is a 10811-60111. The only added spec on it
> >> is a 1x10^-11 ADEV spec at 1 second. By modern standards that's
> >> not a real tight spec. There are other 10811's with tighter specs
> >> on them at 1 second. My guess is that it was not a real tight
> >> spec for the 10811 to hit.
> >>
> >> The short term would appear to contribute to the total error on
> >> the counter. Why not put a better oscillator in it?
> >>
> >> Bob
> >>
> >>
> >>
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> >
> >
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