[time-nuts] Re: A beginner's question.

[Bob Camp]

Hi

One suggestion: 

While you have the counter sitting there, play with the trigger settings and input levels. 
You may find a way to improve things a little bit. No need to go to the 1000 second level.
A 100 second run looking at 1 and 10 second data will tell you what you need to know. 

Bob

> On May 14, 2023, at 1:21 PM, ordnit via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> Hi all,
> I've been reading the ML for quite a long time. In the last weeks I managed to have some spare time to try some measurements, just to see how far is "reading" from "trying".
> 
> My lab is made up of a pair of GPSDO (UCCM modules with an external antenna and good sky coverage), a 53131A and a pair of quartz oscillators that were ripped from some scrap instruments.
> 
> Before trying to measure ADEV on a OCXO, I just wanted to see how deep is the noise floor with my setup. I read in old post (2012) that I could perform some tests using a the PPS output from the GPSDO, a power splitter and two coaxial cables of different lenght. So i put the counter in "t1 to T2" mode, auto-trigger on channel OFF and performed a very long ADEV analisys in TI mode.
> 
> Results I found were, in some ways, encouraging (to me):
> 1s	Sigma(tau) 	6.59E-10
> 10s			6.96E-11
> 100s			7.12E-12
> 1000s			7.01E-13
> 
> Tomorrow I'm going to perform more tests in fequency mode, by looping the 10MHz out of the counter, to its channel 1 input and performing ADEV analisys to. According to what I read, results should be quite different.
> 
> My question is: am I going on the right way? Are the tests I performed somewhat meaningful?
> 
> Thanks in advance.
> 
> Best regards.
> 
> adelmo
> 
> References:
> Best counter setting for ADEV? - Time-nuts ML Oct 1 2012
> Recommended parameters for Timelab ADEV analysis - Time-nuts ML Nov 15 2012
> Measuring ADEV for a beginner - Time-nuts ML Nov 1 2014
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