[time-nuts] Is my Cs C-Field set OK or do I need to take more data?

[Brooke Clarke]

Hi Poul:

Ha    ha    ha   you give me a chuckle.  Probably because that's the 
problem, when to stop and change something.
I'm thinking I might be able to keep this test going and at the same 
time get a GPS direct 1 PPS for comparison.  I think the PRS10 is adding 
a variable that actually makes the test harder than it needs to be.  I 
was hoping that the PRS10 would act as a flywheel to smooth out the GPS, 
but I think it's more like a roller coaster.  After posting the plot and 
watching a movie the data went back down to the 32 ns area and so the 
data has taken on a completely new flavor.

Thanks for the laugh,

Brooke

Poul-Henning Kamp wrote:

>In message <41E1D768.1090305 at pacific.net>, Brooke Clarke writes:
>  
>
>>Hi:
>>
>>For the last few days I've been tweaking the C Field setting on a FTS 4060/S24.  Here's some data taken using the 1 PPS output of a GPS disciplined Rb oscillator (PRS10) as the "A" trigger input to an SR 620 TI counter.  The "B" stop input is the 1 MHz output from the Cs source.
>>http://www.pacificsites.com/~brooke/pdf/sn1013_C-Field.pdf
>>
>>The plot Y-zxis is ns of Time Interval and the X-axis is seconds of run time.
>>
>>A linear fit line has the equation
>>ns of TI = 0.0059X + 30.283.
>>Since this is ns/sec the drift rate of the Cs is 5.9E-12. 
>>
>>So when measuring against a GPS based reference is is fair to say
>>that you need to measure until the TI gets above something like 200
>>ns or the elapsed time exceeds some number? Or do I need to take
>>more data before I change the C-Field setting?
>>    
>>
>
>"As you run your experiment you will get to a point where you are confident
>in your result and conclusion and you will be tempted to stop it.  You
>should run at least twice and preferably three times as long in order to
>convince the rest of us"
>
>				-- my physics prof
>
>
>  
>

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