[time-nuts] MT3339 PA6H and Racal Dana GPIB, update

Bob Camp lists at rtty.us
Wed Dec 12 19:32:47 UTC 2012


20 hours should be 20*60*60 = 72000 samples. The graphs appear to show about
17,000 samples.

If the results do cover a 20 hour period and do not have drift removed,
that's a good FE5680. 1.4x10^-14 is an amazing number for one of those.


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Fabio Eboli
Sent: Wednesday, December 12, 2012 2:10 PM
To: time-nuts at febo.com
Subject: [time-nuts] MT3339 PA6H and Racal Dana GPIB, update

Racal 1992 GPIB, to Chuck Forsberg:
thank you, I will go to see your work.

A little update, after about 20 hours this
is the logging situation:

Not bad, seem the GPS chipset jitter claim
of 10nS is real, what do you think.
Could this unit be a decent one for a GPSDO

The values are the difference from 1s value in ns:
Blue: (1-Period)*1E9, left y axis
Red: Boxcar average 100 samples, right y axis
Yellow: same as red 1000 samples.

I had only few glitches, that are filtered out
in the previous calculations:
one with a reading of precisely 1,5s (the negative one)
and a periodic lack of record, the positive values.

This Rb unit seem pretty close to the mark, more than
another unit I have. I'm thinking to try the other method
Azelio Boriani advised me to do (26 november 2012),
using the pps output from this Rb as a reference.

If I understand well, I should use the Rb as start and
the GPS as stop on the counter, measuring the phase,
and I should see a very long time before the signals
cross. The pulses relative position will be obtained
with a little luck :)


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