[time-nuts] 5370B OCXO

[Bob Camp]

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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