[time-nuts] A beginner's question.
ordnit
ordnit at yahoo.it
Sun May 14 17:21:53 UTC 2023
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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