[time-nuts] 5370B OCXO

[Bob Camp]

Hi

Tough to believe that HP worried a lot about SKU inflation back when they
did the 5370 :)....

I'm assuming that the 5370 was a Santa Clara design. That would put the
counter designers down the hall from the oscillator factory. Unlikely that
there was a communications gap about what could or could not be done.

You may well be correct though. Setting up and managing another part is the
most likely reason why not to add a couple more tests.

Bob

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of paul swed
Sent: Friday, March 12, 2010 8:51 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] 5370B OCXO

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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