[time-nuts] HP5065A environmental sensitivities

cdelect at juno.com cdelect at juno.com
Thu May 12 21:29:08 EDT 2016


                    HP 5065A Environmental sensitivity
 
First here is a comparison between the specified sensitivities of various

Rubidium units.
 
               Barometric per mbar          Temperature per degree C
 
HP 5065A        6.3X10-14                  1.6X10-12
M100 FRK         8.7x10-14                  2.4X10-12
LPRO            1.0X10-13                  6.0X10-12
FE5650A         unspecified                 1.1X10-11
FRSC            1.0X10-13                  1.1X10-11
PRS10            unspecified                1.0X10-11
 
As you can see the HP specs are better than the others!
 
After much effort I managed to measure the actual sensitivity of a 5065A
on my bench. 
It was much better than the spec at 1.55X10-14/mbar! I then installed 
a barometric compensation circuit consisting of a sensor and OP amp. This
feeds the C-field circuit in the 5065A.
After alignment the sensitivity was so low that it was below my 
measurement noise floor!
 
Attached is a frequency plot that illustrates the correction. On the left
is a calibration offset from the Maser of plus/minus 1.84X10-12. The
middle section shows the frequency with the compensation on during
several cycles of plus/minus 35 mbar. The right is with compensation off 
and the plus/minus 35mbar excursions.
 
Also attached is a schematic of the compensation circuitry. 
 
Now I'll work on the temperature sensitivity. Poul-Henning has explored 
in this area and has some good information to start with.
 
Cheers, 
 
Corby
-------------- next part --------------
A non-text attachment was scrubbed...
Name: BARO3.gif
Type: image/gif
Size: 12531 bytes
Desc: not available
URL: <http://www.febo.com/pipermail/time-nuts/attachments/20160512/3c4056b3/attachment-0001.gif>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 468avgajp.jpg
Type: image/jpeg
Size: 23494 bytes
Desc: not available
URL: <http://www.febo.com/pipermail/time-nuts/attachments/20160512/3c4056b3/attachment-0001.jpg>


More information about the time-nuts mailing list