Moin, Most OCXOs have a 50Ω output, which suggests that they expect to be terminated with 50Ω. Now on a normal PCB the wire from the OCXO to the rest of the circuit is usually rather short (1-5cm) which means that it is much less than the wavelength of the 10MHz output. Even when looking reflections, a 2*5cm path (ie forward and back again) would be less than 500ps (in the order of 300ps for FR4). My guess would be that a non-50Ω termination would not result in any adverse effects as the paths are short and the reflections would be constant. The changes that would affect the delay would be temperature and humidity (mostly humidity in this case) which are both rather slow and my guess would be that the added instability would be drowned in the temperature and aging drift of the OCXO.
So, I'd say that it would be still ok to use 1-10kΩ termination impedance without any problems. Is this assumption correct? Is there anything I am missing? Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neil Stephenson _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.