[time-nuts] Re. DIY atomic "resonator"-- replacing SDRs

Alex Pummer alex at pcscons.com
Tue Apr 11 14:25:16 EDT 2017

YES SDRs [step Recovery Diodes] is hard to find today, but there many-- 
PIN -- diodes, which exhibits that effect, even some standard rectifier 
diodes could be used for, despite of that Magnus is right, today are 
better solutions available e.g. PLLs with 10GHz prescalers




On 4/11/2017 9:22 AM, Magnus Danielson wrote:
> 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
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2016.0.8012 / Virus Database: 4769/14290 - Release Date: 
> 04/11/17

More information about the time-nuts mailing list