[time-nuts] CW12-TIM vs M12M and the world

SAIDJACK at aol.com SAIDJACK at aol.com
Fri Mar 30 23:17:45 UTC 2012


Hi Ed,
 
attached more data from the FTS250 CW module. I had it running for a couple 
 of hours, then I removed the antenna (without disturbing the FTS250 
module) for  only a minute and a half to test holdover.
 
We can see a massive phase jump of about 420ns. The M12M and M12+ receivers 
 will not generate 1PPS signals with this type of error if TRAIM is 
enabled, they  would simply not generate 1PPS signals until they are stable again.
 
The frequency jump was about 1.2E-07. Quite massive. This is one of the  
differences between an NCO based unit such as the CW module and a GPSDO type 
of  product.
 
I also included a longer ADEV plot, in which the unit was always locked to  
GPS (the phase jump is not part of this plot).
 
bye,
Said
 
 
In a message dated 3/30/2012 12:58:17 Pacific Daylight Time,  
azelio.boriani at screen.it writes:

Actually  I don't have a good reference (Z3815A): I'm still preparing my
first  disciplined Rb and have 2 Fluke PM6681s. I'm waiting for my SR620,  
it
should be on its way to Italy right now. I have 2 TBolts but not yet  turned
on. What kind of reference have you  used?


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