[time-nuts] Thunderbolt PPS output

Scott Mace smace at intt.net
Sat Aug 9 18:40:37 EDT 2008

Has anyone used the thunderbolt PPS output with a N8UR FatPPS?  I'm seeing
a large (+-100-300us) amount of jitter on the output of the FatPPS.  This same
setup works fine with the input from z3801a (using a PECL/TTL converter)
or the Fury (even though the Fury's pulse is wide enough to begin with).
Is there something special about the thunderbolt PPS output?  I noticed it
seemed to require 50ohm termination to get a clean signal when I connected
it to a counter (5334a) with a 3 foot cable.

I'm using the FatPPS in conjunction with a soekris 4501 with the tmrin mod.


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