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

Ulrich Bangert df6jb at ulrich-bangert.de
Sun Nov 12 07:46:20 UTC 2006


Bruce,

> The manual for the SRS PRS10 states that the combined effects of the 
> buffer gas and the pump lamp spectral profile shift the 
> resonance about 3kHz from the unperturbed natural transition
frequency.

Ok, this is a word!

> Perhaps Efratom relied on the reproducibility of lamp characteristics,

> buffer gas pressure, buffer gas composition during the manufacturing 
> process whilst HP allowed for  variations in these parameters 
> from one physics package to another.

This has been one of the original ideas! Basically this thread has been
started to find out whether the physics of an rubidium standard would
allow for such an idea.

Cheers
Ulrich

> -----Ursprüngliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Dr Bruce Griffiths
> Gesendet: Sonntag, 12. November 2006 00:55
> An: Discussion of precise time and frequency measurement
> Betreff: Re: [time-nuts] New PLOTTER version / HP5065 
> Frequency processing part II
> 
> 
> Ulrich Bangert wrote:
> > 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
> >
> >
> > _______________________________________________
> > time-nuts mailing list
> > time-nuts at febo.com 
> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >
> >   
> Ulrich
> 
> The manual for the SRS PRS10 states that the combined effects of the 
> buffer gas and the pump lamp spectral profile shift the 
> resonance about 
> 3kHz from the unperturbed natural transition frequency. With 
> a different 
> buffer gas, lamp spectral profile, or buffer gas pressure the 
> resonance 
> shift will be different for different physics packages.
> Perhaps Efratom relied on the reproducibility of lamp 
> characteristics, 
> buffer gas pressure, buffer gas composition during the manufacturing 
> process whilst HP allowed for  variations in these parameters 
> from one 
> physics package to another.
> 
> Bruce
> 
> _______________________________________________
> time-nuts mailing list
> time-nuts at febo.com 
> https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts
> 





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