[time-nuts] Trimble Tbolt temperature

[Azelio Boriani]

'The temperature chip is there to “learn” the TC of the unit while it
is in lock.'
I think this is news for the group: as of my knowledge, we don't know
if the 1620 has an active role in the TBolt other than measuring
temperature for the TSIP output.

On Wed, Dec 4, 2019 at 4:04 PM Bob kb8tq <kb8tq at n1k.org> wrote:
>
> Hi
>
> The temperature chip is there to “learn” the TC of the unit while it is in
> lock. If and when the unit goes into holdover that information is used
> to compensate the unit. If the environment does not change much when
> you are in holdover this may be a benefit. If the HVAC goes when the
> holdover happens …. maybe not so much.
>
> The DAC and voltage reference  on the E-911 TBolts has a pretty
> substantial temperature coefficient. On top of the wide tune range of the
> OCXO this gives thepart a pretty substantial temperature wander. If holdover
> is part of the “plan” the temperature chip probably is worth having.
>
> The Nortel GPSDO’s have a very different OCXO in them (normally a double
> oven) with a narrower tuning range The DAC and voltage reference are
> done very differently as well. On top of that, the Nortel spec for holdover
> was much tighter than the E-911 requirement . Net is that the temperature
> chip in the Nortel versions may not be as important, even in holdover.
>
> Yes, way more than you wanted to know …...
>
> Bob
>
> > On Dec 4, 2019, at 2:52 AM, Christophe Huygens <christophe.huygens at kuleuven.be> wrote:
> >
> > Thanks all - if of no consequence, case closed.
> >
> > On 04/12/19 03:03, Tom Van Baak wrote:
> >> Most TBolt measure board temperature to about 1/100th C resolution.
> >> This is the correct behavior. Some TBolt report temperatures that seem
> >> to step in 1 C increments, or they report a constant -55 C, or they
> >> glitch once in a while. These are bugs.
> >>
> >> You can replace the DS1620 chip if you want. It's perhaps best to
> >> locate the 20-year old version of the chip. There are lots of threads
> >> about this in the archive.
> >>
> >> The DS1620, working or not, has no effect on the performance of a
> >> running TBolt. So I've never bothered replacing any of mine. It may
> >> have a slight effect on extended holdover performance. It's a long
> >> story and I'm not sure if anyone has actually verified or quantified
> >> this.
> >>
> >> Here's additional info about the TBolt & DS1620; it's more complex
> >> than you think:
> >>
> >> "Strange temperature peak"
> >> https://lists.febo.com/pipermail/time-nuts_lists.febo.com/2011-May/039188.html
> >>
> >>
> >> "Trimble Thunderbolt GPSDO Temperature Sensor Details"
> >> http://leapsecond.com/pages/tbolt-1620/
> >>
> >> "Dallas state machine glitch"
> >> https://www.digitemp.com/docs/ds1820-report.pdf
> >>
> >> /tvb
> >>
> >>
> >> On 12/3/2019 1:47 AM, Christophe Huygens wrote:
> >>> Hi all,
> >>>
> >>> I am back on time-nuts after many moons.
> >>>
> >>> Lady heather shows constant -55deg C for my Tbolt.
> >>>
> >>> all else seems to function fine (is in a constant T environment, sort
> >>> of)
> >>>
> >>> Any thoughts....
> >>>
> >>> br and thanks
> >>>
> >>> Xtof
> >>>
> >>> _______________________________________________
> >>> time-nuts mailing list -- time-nuts at lists.febo.com
> >>> To unsubscribe, go to
> >>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> >>> and follow the instructions there.
> >>>
> >>
> >>
> >> _______________________________________________
> >> time-nuts mailing list -- time-nuts at lists.febo.com
> >> To unsubscribe, go to
> >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> >> and follow the instructions there.
> >
> > --
> > --
> > http://distrinet.cs.kuleuven.be/people/showMember.do?memberID=u0013167
> > prof. dr. ir. Christophe Huygens  iMEC-KULeuven-DistriNet
> >
> >
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at lists.febo.com
> > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> > and follow the instructions there.
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.