[time-nuts] Stepping up the output of an OCXO
Dr Bruce Griffiths
bruce.griffiths at xtra.co.nz
Sun Feb 4 12:22:54 UTC 2007
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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