[time-nuts] HP5065B !!!

EWKehren at aol.com EWKehren at aol.com
Mon Apr 29 21:38:46 EDT 2013


I never came to that conclusion. There is enough work out there with  
results. My comment was to that particular paper that did not measure up to the  
work Corby has been doing. Still trying to figure out the purpose of the  
posting.
Bert Kehren 
 
 
In a message dated 4/29/2013 6:34:24 P.M. Eastern Daylight Time,  
bruce.griffiths at xtra.co.nz writes:

Since  performance improves as the bandwidth of the "lamp" spectrum 
decreases its  not unreasonble to suggest that a suitable laser source 
may improve  performance further.

The following paper (and theoretical  considerations) indicate that your 
conclusions regarding the potential  performance of a laser pumped 
rubidium standard are  incorrect.

http://tf.boulder.nist.gov/general/pdf/1219.pdf

The  addition of second harmonic traps tuned to the 2nd harmonic of the  
modulation frequency of the resonance interrogation signals should  
improve the performance  considerably.


Bruce

EWKehren at aol.com wrote:
>
>  I am still sitting here trying to figure out the purpose  of posting  the
> article on laser diode pumping of the Rb. One look at the  data  and it is
> clear that Corby’s work far surpasses the data  shown in the paper. All  
it does
> is distract from Corb’s  accomplishments. Lets be clear, Corby has opened
> the door of H Maser  performance for those that have a HP 5065A. Not all 
work
> is  done  but a giant step has been accomplished, the challenge now is to
>  continue  the work. In simple terms it gets down to keep the A/V slope  
from
> turning  upward. Work is going on off list to address some  of the issues 
and
> maybe some  one is willing to contribute. But  what the list at a whole 
can do
> is contribute  data as to HP  5065A performance. There are quite a few 
5065A’s
> out there but   very little data besides HP spec. To better tackle the
> flattening of  the curve,  aging, temperature sensitivity, barometric 
pressure
>  sensitivity and even  humidity sensitivity has to be understood. It  is
> unrealistic to get past 1 E-13  unless this is understood and  
compensated for. Also
> some of these parameters  will vary from  unit to unit and some degree of
> tailoring to a particular unit   has to be considered in the design. Some 
tests
> have to be done by  those members  that have access to a Maser.
> Also Corby   found out that units with older A3 modules did not get the
> performance  boost but  replacement of A3 did get the super performance. 
That
>  confirms my suspicion that  there is room for work on frequency  
generation. PRS
> 10 does a direct  frequency generation. Somehow  using the  step recovery
> diode as a mixer obviously works but is  it optimum, or is there a  
better way
> to generate the resonator  frequency? What is key to get the best  signal 
and
> S/N  ratio?
> When previously mentioning aging control, concern was   voiced as to 
getting
> in to the HP 5065A. Corby’s work gets to the hart  of the  unit, the RVFR,
> but Corby has gone four for four.   Adding control will only move the two 
C
> field wires to the analog  board and using 30 mA from the unit. Unit can
> easily  restored to  its original condition as far as frequency control is
>  concerned.
> Obviously the RVFR is the big differentiator in the   HP5065A and I know 
of
> no commercially available unit that even gets  close but  once the work is
> complete a look at a FRK may be in  order, I doubt it will ever  be as 
good,
> but there is room for a  filter and the physics part is considerable  
larger
> than today’s  units.  Some  other units may be using a filter but the  
physics
> package is so small that  compromises had to be made and  the goal was 
more
> cost than ultimate performance.
> It is up to  the list to turn this in to a Maser like  performance with 
out
>  mortgaging your home.
> Bert Kehren
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