[time-nuts] HP/Agilet counter 53131A (not 53151A) trigger problems

Rick Karlquist richard at karlquist.com
Mon Aug 27 19:15:45 EDT 2012


Several decades ago, the concept of the "smart clock" arose
at what was then HP.  The idea was as discussed here to
"characterize" past aging, "predict" future aging, and
then "correct" the aging.  The goal wasn't to turn a quartz
oscillator into an atomic clock replacement, but simply
to get the oscillator through a 1 hour or so "holdover" time
during GPS outages.  It sort of worked for that very limited
purpose, but in general, past performance of HP crystals wasn't
a very good predictor of future results.  Crystals would age
in one direction for a while and possibly slow down as time
when on, but then then might start aging in the other direction.
There were also frequency jumps that were substantial and totally
random.  The reason why the HP crystals were unpredictable was
that all the deterministic processes such as mass preferentially
depositing on the crystal, so as to make the frequency age
lower, had been eliminated by years of manufacturing improvements.
The remaining processes were of the nature of quartz stress
relaxation that were very random.

Rick Karlquist



Don Latham wrote:
> There are ways of generating models, such as ARIMA, using past behavior
> and the models used to tweak filters and so on. The shifts would have to
> be accounted for as they occur, seems to me. Now the interesting
> possibility is that a shift does not alter the underlying model for a
> given crystal????
> Has to be tested.
> Don
>
> Azelio Boriani
>> So it can't be done... the possibility to discipline an OCXO taking the
>> action from a suitable model should help in speeding up the adjustments
>> and
>> avoiding the humps as seen in the Allan deviation plot.
>>
>> On Mon, Aug 27, 2012 at 9:31 PM, Don Latham <djl at montana.com> wrote:
>>
>>> Isn't crystal aging marked by random jumps? perhaps lattice
>>> rearrangement? Really hard if not impossible to model...
>>> Don
>>>
>>> Azelio Boriani
>>> > 30mV are -13dBm so maybe it is why the -20dBm is not a suitable
>>> level
>>> > for
>>> > that input. I have the 53132A and the 53181A so I can test (with the
>>> R&S
>>> > SML01). Is this problem new? Never tested before?
>>> >
>>> > About the OCXO aging: OK, I'm interested in the development of a
>>> model
>>> > that
>>> > can be general enough so that it can be "steered", adjusting its
>>> > parameters, during the OCXO life. The data (to adjust the
>>> parameters)
>>> > will
>>> > be gathered by the continuous monitoring with the GPS.
>>> >
>>> > On Mon, Aug 27, 2012 at 7:01 PM, Bernd Neubig <bneubig at t-online.de>
>>> > wrote:
>>> >
>>> >> Hi Azelio,
>>> >>
>>> >> Sorry, the counters are 53131A, not 53151A. The A and B inputs are
>>> >> specified
>>> >> from DC to 225 MHz with a sensitivity of y20 mV (rms) up to 100
>>> MHz,
>>> >> <30 mV
>>> >> (rms) 100 ~ 200 MHz, and <50 mV (rms) 200 ~ 225 MHz.
>>> >> The problem can be at either input alone. The problem is only in
>>> the
>>> >> range
>>> >> between 100 MHz and <200 MHz, observed in automatic trigger mode.
>>> In
>>> >> manual
>>> >> trigger mode the counter does not trigger at all in that freq
>>> range.
>>> >>
>>> >> I cannot tell you an aging model for a particular OCXO, and I doubt
>>> if
>>> >> anyone can ;) Aging predictions can only be made on individual
>>> OCXO,
>>> >> unit
>>> >> by
>>> >> unit, and the prediction is only valid over a rather limited time.
>>> >> Therefore
>>> >> you must continuously monitor and update your prediction.
>>> >>
>>> >> Best regards
>>> >>
>>> >> Bernd
>>> >> DK1AG
>>> >>
>>> >> -----Ursprüngliche Nachricht-----
>>> >> Von: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]
>>> Im
>>> >> Auftrag von Azelio Boriani
>>> >> Gesendet: Freitag, 24. August 2012 17:28
>>> >> An: Discussion of precise time and frequency measurement
>>> >> Betreff: Re: [time-nuts] HP/Agilet counter 53151A trigger problems
>>> >>
>>> >> From the datasheet:
>>> >> A input 10Hz..125MHz min level 25mVrms (-19dBm) B input min 50MHz,
>>> >> -20dBm
>>> >> the problem is on A input only? Maybe 150MHz for the A input, being
>>> >> beyond
>>> >> the official specifications, requires more signal on one counter
>>> than
>>> >> the
>>> >> other. In the past they all were fine?
>>> >> I have read your paper on the correlation between the real and
>>> >> predicted
>>> >> aging of crystal oscillators. I'm trying to find a suitable model
>>> for
>>> >> the
>>> >> Morion MV201 OCXO or the Oscilloquartz 8663 to implement a Kalman
>>> >> filter.
>>> >>
>>> >> On Fri, Aug 24, 2012 at 3:34 PM, Bernd Neubig <BNeubig at t-online.de>
>>> >> wrote:
>>> >>
>>> >> > Hi all,
>>> >> >
>>> >> > I have several HP/Agilent frequency counters 53151A (and 53152A)
>>> in
>>> >> my
>>> >> lab.
>>> >> > Several of them meanwhile show trigger problems.
>>> >> >
>>> >> > I have tested the A and B channel between 5 MHz and 200 MHZ at
>>> three
>>> >> > input levels of -10 dBm, 0 dBm and +10 dBm.
>>> >> >
>>> >> > Those with trigger problems show erroneous numbers at -10 dBm
>>> input
>>> >> > level rather selectively, i.e. mostly at 100 MHz, some also at
>>> 150
>>> >> > MHz, while the are o.k.
>>> >> >
>>> >> > Has anyone on this list experienced similar defects and can give
>>> a
>>> >> > recommendation how to fix/repair them?
>>> >> >
>>> >> >
>>> >> >
>>> >> > Best regards
>>> >> >
>>> >> >
>>> >> >
>>> >> > Bernd
>>> >> >
>>> >> > DK1AG
>>> >> >
>>> >> > www.axtal.com
>>> >> >
>>> >> > _______________________________________________
>>> >> > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go
>>> to
>>> >> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> >> > and follow the instructions there.
>>> >> >
>>> >> _______________________________________________
>>> >> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
>>> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> >> and follow the instructions there.
>>> >>
>>> >>
>>> >> _______________________________________________
>>> >> time-nuts mailing list -- time-nuts at febo.com
>>> >> To unsubscribe, go to
>>> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> >> and follow the instructions there.
>>> >>
>>> > _______________________________________________
>>> > time-nuts mailing list -- time-nuts at febo.com
>>> > To unsubscribe, go to
>>> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> > and follow the instructions there.
>>> >
>>> >
>>>
>>>
>>> --
>>> "Neither the voice of authority nor the weight of reason and argument
>>> are as significant as experiment, for thence comes quiet to the mind."
>>> R. Bacon
>>> "If you don't know what it is, don't poke it."
>>> Ghost in the Shell
>>>
>>>
>>> Dr. Don Latham AJ7LL
>>> Six Mile Systems LLP
>>> 17850 Six Mile Road
>>> POB 134
>>> Huson, MT, 59846
>>> VOX 406-626-4304
>>> www.lightningforensics.com
>>> www.sixmilesystems.com
>>>
>>>
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com
>>> To unsubscribe, go to
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
>>
>
>
> --
> "Neither the voice of authority nor the weight of reason and argument
> are as significant as experiment, for thence comes quiet to the mind."
> R. Bacon
> "If you don't know what it is, don't poke it."
> Ghost in the Shell
>
>
> Dr. Don Latham AJ7LL
> Six Mile Systems LLP
> 17850 Six Mile Road
> POB 134
> Huson, MT, 59846
> VOX 406-626-4304
> www.lightningforensics.com
> www.sixmilesystems.com
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>






More information about the time-nuts mailing list