On 04/11/2017 05:54 PM, Richard (Rick) Karlquist wrote:
On 4/11/2017 12:31 AM, Andre wrote:
Has anyone else either built an atomic clock around a bare Rb lamp
module "core" or attempted
Not a DIY project, but I was the RF designer on the HP 10816 rubidium
standard, which never made it to product introduction (a half dozen
working pilot run units were built in 1982). I would say this task is
probably beyond the scope of a DIY project, at least for most
time-nuts.
Probably right.
The Rb lamp drive circuit (particularly getting the
lamp to light up) is very challenging.
There would be none. It would be replaced by a laser. That has its own
set of "problems" but different.
The step recovery diode multiplier is very challenging.
Today you would not go the SRD route in synthesis.
Besides, SRDs can be hard to find these days.
The photodetector and loop integrator is non trivial.
I'd expect the loop integrator to be done in digital, which eases up on
some of the design problems.
The synthesizer is the one thing that is easy in 2017.
Indeed-
> The oven is also no simple thing to get
low tempco. Unlike a crystal, you have a lot of heat being
generated by the lamp, etc. The lamp needs to be at a different
temperature than the other cells.
Going down the laser-route, the balance of temperature between the cells
is no longer a relevant problem. Further, the lamp and its heat is gone.
You have to keep the tip
off at the lowest temperature to keep the Rb in place and not
"flood" the cell and block the light. Etc., etc.
You still have this problem, but not as a lamp problem but only for the
resonance cell part.
This is in the category of projects where if you were qualified
to do it, your time is far too valuable to do it for the amount
of money you would save.
This is the type of project you do not to save any money, but to spend
and learn.
Even if done in a much more modern fashion, avoiding several of the
traditional problems, there is plenty of issues to solve and handle.
Cheers,
Magnus
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