[time-nuts] Mains as time-reference

Tom Van Baak tvb at LeapSecond.com
Wed Dec 29 19:01:46 UTC 2010


Magnus,

See fellow mains measurement men:

http://www.xs4all.nl/~rjoris/gridfrequency.html
http://www.vf.utwente.nl/~ptdeboer/misc/mains.html
http://www.leapsecond.com/pages/mains/

/tvb

----- Original Message ----- 
From: "Magnus Danielson" <magnus at rubidium.dyndns.org>
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
Sent: Wednesday, December 29, 2010 10:45 AM
Subject: [time-nuts] Mains as time-reference


> Fellow time-nuts,
> 
> Just for fun I have been looking at the mains as a time-reference.
> 
> I've used an OSA 8600 as reference and divided down to PPS by a TADD-2. 
> While not absolute time reference, it is way quieter than the mains so I 
> think it is good enough to have some fun at least. Just to illustrate 
> the issue.
> 
> I use a HP5335A to measure the time from PPS to rising edge of 50 Hz as 
> being accessible through a transformer.
> 
> The ADEV has a peak at 30 s measuring 2,3E-4 and another at 6000 s 
> measuring 4,3E-4.
> 
> The phase changes over -0.11923 to +10,979 so a time difference 
> peak-to-peak of 11,098 seconds.
> 
> While I could refine my measurements to ensure trigger jitter is not 
> causing any major issues, the ADEV slope from 1 s is rising rather than 
> lowering, so it rather seems like source behaviour dominates.
> 
> While this attempt is a hack, I hope it inspires people to fiddle around 
> a little. :)
> 
> Cheers,
> Magnus





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