[time-nuts] ensemble of standards

Magnus Danielson magnus at rubidium.dyndns.org
Sun Dec 30 03:32:27 UTC 2012

On 30/12/12 02:46, cdelect at juno.com wrote:
> Also about ensembles,
> http://www.mksa.deit.univpm.it/biblioteca/sala_tecnica/scaffale_strumenti
> /Campioni/EPSG070861.pdf
> This article describes combining 4 HP 5071A standards.
> Description on page 2 and block diagram in figure 2.
> Unfortunately no details on the controller are given!
> It's what I'd like to do to two or more HP 5065A
> Anyone know what they did in the controller?

I'd assume that this is similar to what is described in Chapter 9 of NBS 
Monograph 140, by Dr. David Allan and friends:


When reading the FORTRAN code, one has to realize that the ER 
calculations is hard-wired to the way that the NBS setup at the time 
where done, so that the 8 clocks was compared by a number of pair-wise 
measures and that the time-differences is combined as needed where some 
of the clocks becomes transfer standards in the comparison back to the 
primary reference standard. Clock 3 is the main clock in the hookup.

A modern view on things is found here:

The original time-scale algorithm ran on a PDP-8 machine with 4k word 
memory, coded in Fortran by Dr. Allan. Today they run using a pair of 
redundant 386 machines and using a blend of Jim Greys buffer and mixers 
and that of commercial time-interval measurement rig.


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