[time-nuts] Hydrogen maser frequency jumps

Attila Kinali attila at kinali.ch
Sat Dec 5 07:55:37 EST 2015


On Sat, 5 Dec 2015 12:16:44 +1100
Jim Palfreyman <jim77742 at gmail.com> wrote:

> Has anyone here who is familiar with hydrogen masers ever experienced a
> sudden jump in phase of the 5MHz output?
[...]
> The weird thing is that the jump is ~0.7ns and that 1/0.7E-9 is close-ish
> to 1420.4MHz which is the hydrogen line. Too much of a coincidence for me.
> 
> These seem to be appearing at three different locations with the same model
> of maser at each location. I won't mention the model publicly.

You should at least say what kind of maser it is and what the
synthesis chain looks like. Otherwise it will be only wild guesses.

If you have an active maser, then it is most likely that you have
a cycle slip due to weak signal (or low SNR), as PHK has written.

If it's a passive maser, that explanation doesn't work, as the
synthesis chain works the other way round (loosely speaking)
and uses an FLL on the atomic transition.

			Attila Kinali
-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
                 -- Miss Matheson, The Diamond Age, Neil Stephenson



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