The Thunderbolt data sheet says that the unit requires 25mA at 12V. That spec would imply it is for a unit without an OCXO since the oven heater draws considerable current from the 12V power supply. But then, the data sheet says it draws 15 watts cold, 10 watts steady state. That implies the unit has a heater. And if you multiply the published power supply requirements out you get 2 watts, not 10-15 watts. It appears that some of the specs are for an ovenless unit, others are for the ovenized unit.
The data sheet also talks about a telecom version with improved holdover performance... this has got to be the ovenized unit. I suspect the Allan variance plot is for the low end unit, but the shape of the curve is funny. It always slopes downward. Almost all GPSDO Allan variance plots show a hump in the graph around 100 seconds. Trimble's numbers and graph shape do seem to relate closely to my "auto-Allan variance" plots of the OSC offset data supplied by the unit (where the tiiming reference is its own interpretation of the GPS time signal). _________________________________________________________________ Need to know now? Get instant answers with Windows Live Messenger. http://www.windowslive.com/messenger/connect_your_way.html?ocid=TXT_TAGLM_WL_messenger_072008 _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
