Ulrich Bangert wrote:
Bruce,I have seen this specs before but do you know how to find the schematics? Best regards Ulric Bangert
UlrichSince 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
<<attachment: hpda-5A.jpg>>
<<attachment: hpda5_noise_plotA.jpg>>
_______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
