[time-nuts] Rubidium Performance

Mark Spencer mspencer12345 at yahoo.ca
Sat Feb 4 03:52:45 UTC 2012

Once my first unit has warmed up properly I'll be curious to see how the adev compares (I can't measure phase noise.)  If any one is interested I've also got some adev data from my one working temex lpfrs Rb unit.   (I also have another unit that only locks once in a while.)    At approx 1/3 the price the 5680 seems like a better bargain especially if the 1pps output works.

Thanks in advance to those who can properly evaluate these units.   

Regards Mark S

On 2012-02-03, at 7:19 PM, "John Miles" <jmiles at pop.net> wrote:

>> Someone earlier today made the point that for all the talk about the FEI
>> rubes, there hasn't been any real performance info posted.  That prodded
>> me to start an experiment I've been meaning to do for a while.  I have
>> samples of all three of the common telco Rb standards -- Efratom FRS,
>> Datum LPRO, and Fe8-5680.
>> Over the next couple of days I'll do measurement runs of each of the three
>> versus an HP-5065A laboratory Rb (for ADEV), and a Wenzel ULN (for phase
>> noise).  I'll collect long enough to get solid ADEV out to at least 1000
> second
>> tau on each unit.  I have the FRS test running now.
>> If all goes well, I'll post the results early next week.
> I'm doing some short-term runs on the ones I have around here, as well
> (FE-5680A, PRS-10, LPRO).  Will be interesting to see how close ours are. 
> So far, the FE-5680A is doing well in the ADEV department, but its AD9832
> DDS chip adds some substantial noise and spurs to the 10 MHz output.  Does
> yours have that chip?  I understand that some of them didn't.
> The overall SSB C/N ratio I'm seeing between 1 Hz - 100 kHz is pretty much
> in line with Analog Devices' data sheet, as are the spur levels.  
> -- john
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