[time-nuts] Sneaky Errors

Mark Sims holrum at hotmail.com
Wed Oct 19 20:36:18 EDT 2011


I believe that the Thunderbolt firmware would catch such a thing.    There is quite a bit of error checking and TRAIM (time receiver autonomous integrity monitoring) done.

If the osc was off in freq,  the firmware would try to use the EFC voltage to slew it back into agreement with the GPS signal.   If the osc was off freq or not controllable,  the DAC voltage would quickly reach it's control limit and the unit would alarm out.   Of course,  you have to be monitoring the alarms to know this has happened.

Also,  if the osc freq is not accurate,  the unit can not decode the GPS signal since it uses the osc to generate the GPS receiver local oscillator.  If the unit is tracking GPS satellites,  your are pretty much assured that it is working. 		 	   		  


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