[time-nuts] Stepping up the output of an OCXO

[Dr Bruce Griffiths]

Ulrich Bangert wrote:
> Bruce,
>
> I have seen this specs before but do you know how to find the
> schematics?
>
> Best regards
> Ulric Bangert
>
>   
Ulrich

Since the earlier NBS isolation/distribution amplifiers consisted of dc 
coupled cascaded common base stages (according to Magnus who had looked 
at some), the newer generation developed in conjunction with the 
technical university of Torino may merely use the same topology with 
faster transistors (SiGe??) perhaps in IC or hybrid form.

I suspect that the 0.3ps/K may have been a typo and they use amplifiers 
similar to the Spectradynamics Distribution amplifiers rated at 3ps/K. 
These distribution amplifiers  are recommended by the BIPM.
For the 1-20MHz amplifier see:
http://www.spectradynamics.com/HPDA-15.html
See attached files for phase noise plot and mechanical shielding used.

I guess there's a passive splitter in there somewhere and a bandpass 
filter (which probably contributes most of the phase tempco) in there as 
well.

Everyone of note in the professional timing community, including the 
Italians, seems to be buying them.

Bruce

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