[time-nuts] New PLOTTER version / HP5065 Frequency processing part II

[Ulrich Bangert]

Hi folks,

first i would like to announce a new version of PLOTTER which can be
downloaded from

www.ulrich-bangert.de

The new version can classify data and compute new data columns from
existing ones using a formula interpreter in that you may input a
formula of your own. A lot of mathematic expressions are supported.

Second, i would like to say thanks to anybody who answered on my
"Frequency processing scheme of HP5065 rubidium vapour standard" thread.
As usual in this group the (s+n)/n of the answers has been high.
Nevertheless I dare to state that the basic question of mine is still
unanswered. I believe that this is due to English not being my natural
language so perhaps i did not manage to make the question really clear
to everybody. Let me try again.

Rubidium is NOT a PRIMARY frequency standard. Point. This has been well
understood before I put forward my question and a lot of you have
pointed to environmental parameters that may have a influence on the
resonance frequency one may measure with a given physics package. 

The basic question has not been WHY the atomic resonance frequency is
dependend on environmental parameters. The question has been TO WHAT
EXTENT or expressed in other words IN WHICH ORDER OF MAGNITUDE these
environmental parameters have an influence on the resonance frequency.

This question has a very practical background: 

If you look at the schematics of a Ball-Efratom FRK-L rubidium standard
you will notice that it has a fixed frequency synthesizer stage to
generate the microwave frequency from the 10 MHz OCXO. There is NO
possibility to tune anything concerning the microwave frequency of the
physics package OTHER than the C-field setting. Since the C-field
setting covers a frequency range of +/- 1E-9 relative this seems to be a
strong indication that all efects that you decribe (including a exchange
of the physics package) must be WELL below 10E-9 relative. With the
resonance frequency in the 7 GHz region +/-10E-9 makes abt. +/- 7 Hz
absolute. Note that this +/-7 Hz matches pretty much the way how the
rubidium's frequency is usually specified as x.xxxxxx +/- 4 (7)Hz for
example on TVB's pages. Up to this point I am in harmony with the world.

Now comes the strange fact: HP's 5065 is equipped with a tuneable
synthesizer to generate the microwave frequency from the OCXO. HP states
that this tuneable synthesizer can be used to generate a number of
different 'time scales' as some of you also have pointed at. I
understand this very well!

But the STRANGE thing is that HP uses DIFFERENT synthesizer settings
albeit the intended purpose of the tuning ALSO to generate THE SAME time
scale with two different physics packages. 

That is what we found on two different physics packages:

Physics Package 1      C-Field 7.21       Synth. 8619  -   5.31498914
Mhz
 
Physics Package 2      C-Field 8.24       Synth. 8397  -   5.31503431
Mhz

Please note that the two synthesizer setting are different by MORE THAN
45 Hz. This is just one example, other physics packages may perhaps even
be more apart. We have seen above that there is reason to believe that
all environmental influences are smaller than +/-7 Hz. So where comes
this 45 Hz difference from?

Cheers

Ulrich Bangert, DF6JB