[time-nuts] HP 5061Cs reference question
paulswedb at gmail.com
Sat Dec 6 16:12:08 EST 2014
The system does consistently come to lock with a constant offset. So its
finding something. Just the odd little offset thats bugging me.
On Sat, Dec 6, 2014 at 2:48 PM, Magnus Danielson <magnus at rubidium.dyndns.org
> It's a challenge indeed. IF you are running on fumes, it will be harder
> for the automatic locking to find first and second modulations, and if it
> does this, it is much more likely to be the central pedestal as the others
> will be even further down into the noise. The lack of the fundamental tone
> will cause that FLL may fail to lock, since the sweep signal can be too
> strongs, and if it does lock, it will be weak as the loop gain will be off
> by the lack of signal and then naturally the S/N will be problematic.
> Not sure that it in itself will be the cause of systematically drifting of
> the mark, but rather varying a lot around that mark.
> On 12/06/2014 08:16 PM, paul swed wrote:
>> All good answers with a good tube and enough current to read on the meter.
>> But I am working at the very limit of the Cs fumes. There is current,
>> .5 to 1 tick mark on the meter of a 5061 using a 5060 tube.
>> Thats the challenge on a very eol tube.
>> On Sat, Dec 6, 2014 at 1:56 PM, Magnus Danielson <
>> magnus at rubidium.dyndns.org
>>> On 12/06/2014 06:04 PM, Tom Van Baak wrote:
>>>> There are 7 peaks total, about 40 kHz apart (on my 5061A). If you're
>>>> talking about just the central peak, there are two smaller peaks on
>>>> side, about 1 kHz apart. The exact value depends on internal magnetic
>>>> field, which is specific to each beam tube design.
>>>> For some measurements of all the peaks, have a look at:
>>> These are the 7 Zeeman pedestals, and on top of them you have the Ramsay
>>> fringes. You can indeed lock onto the wrong Ramsey-fringe, but they too
>>> have amplitude differences. For a normal tube, they are quite
>>> but if you look at the Ramsay fringes on the NIST-F1, they are much
>>> and looses amplitude much slower, so you need to pay more details of
>>> fringe you use. The density of the Ramsay fringes is due to the
>>> time, which has been one of the driving forces to develop hydrogen masers
>>> and cesium fountains, but for a simple cesium tube, it's a few dm of
>>> distance and the average speed of the cesium steam.
>>> You can play with the C-field in addition to playing with peaks:
>>>> http://leapsecond.com/images/cfield.gif (578 x 4610 pixels)
>>> Which is a good illustration. It would be good.
>>> For more details search the archives for the word Zeeman. For example:
>>>> A nice description from hp how a cesium beam standard works:
>>> Do check the FTS-4065C manual as I just uploaded. Good complementary
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