The test I have been conducting for the last 6 weeks uses a 15V 3A Toshiba
switcher feeding the 5680A through a filter and a 78M05 for the five volts.
For the last 5 weeks I have temperature control and I still se no aging.
As I mentioned before I read 1E-12 over 1000 seconds since Tbolt
Thanks for the pointer on the C-field. Yes, it aligns with the small
hole in the case. A lucky 1/4 counter clockwise turn reversed the drift
from 450 nsec per hour to 200 nsec in 10 hours. That accuracy begins to
rival the GPS signal over the range. I plan to leave it alone for a
couple of
After several weeks of slow evening and hour here and hour there the FEI
5680a is performing on the bench. I was able to get the serial interface
to operate for a brief period. The 'S' and 'F' commands worked long
enough to change the divisor to produce close to a 10 MHx output, it was
7 Hz
I spent quite a bit of time poking and prodding FE5680's.A while back, I
posted a piece about what I found. It covers some important details about
programming these units. The part about setting the frequency is at the end of
the piece. Dieder has it available on his site:
Mark,
Thank you for your work and your reply, I was able to disconnect the
output of the DDS board from the 1 second divider, the DDS board
produces a clean sine wave.
I thank you for your article, I have a couple of follow up questions:
1. Which pot is the C-field?
2. Did you ever
Hello Dan,
I think the C-field pot is the one accessible through the hole in the outer
cover. If you don't have the cover, it is on one side of the physics package
can near the top, center.
I never messed with the reset pin. The RS-232 interface works just fine.
Most of my units are the
Jean-Christophe Deschamps wrote:
Dear group,
I'm a newbie here, so please bear with me.
I'm about to buy a FEI 5680A Rubidium frequency standard off
ebay. From what I've gathered, these units were used in the telco
industry for about 10 years, but are still useable for my needs. I
Rex,
Thank you for your input.
At 21:45 05/03/2008, you wrote:
[===
Other people clearly have units that run on just +15V and do respond
to
serial commands to set the frequency. One person reported they were
able
to adjust the frequency on theirs with a screw
I think that I might purchase a GPS disciplined oscillator instead of
rubidium standard for a cal lab. There's no physics package in danger
of wearing out and no worries about local settings changing accuracy.
They are also low power and something like the Trimble unit is very compact.
jeff
Jean-Christophe Deschamps wrote:
Dear group,
I'm a newbie here, so please bear with me.
I'm about to buy a FEI 5680A Rubidium frequency standard off
ebay.
Jean-Christophe,
Someone else may know better than I, but some (indeed most?) of these
units on eBay do not have a 10 MHz output, only
In the past we have been looking for information on programming the
FEI-5680A rubidium. On Ebay is a rubidium and they person states he can
program the unit, and from the photo's , he has.
Rex, check it out !
On Thu, 09 Nov 2006 21:58:20 -0600, Brian Kirby [EMAIL PROTECTED]
wrote:
In the past we have been looking for information on programming the
FEI-5680A rubidium. On Ebay is a rubidium and they person states he can
program the unit, and from the photo's , he has.
Rex, check it out !
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