Hi, while this is good news for Trimble's competition and may open up the avenue for an amateur mod, I think we would have to be fair to Trimble and do the double-blind test: 1) Put the original temp sensor back into the unit, let it run one week, and do the drift tests exactly the same as before. 2) remove the sensor completely from the board, and let it run without any sensor (if the unit works this way) You may have seen the performance difference due to measurement errors, aging of the crystal, ambient temperature changes (there was over 1 week difference between the two tests, so I am sure ambient temperature effects were different on the two runs), etc. To really get to the bottom of this, you would have to put the unit into a thermal chamber and cycle it from say -20C to +60C over an hour with say 10C steps and see the frequency change versus temperature. bye, Said In a message dated 3/6/2009 09:58:07 Pacific Standard Time, [email protected] writes:
So, it appears that the Thunderbolt does indeed use the temperature sensor readings in its disciplining of the oscillator (which is also obvious from the plots of DAC voltage vs temperature) and that the units performance (at least the holdover performance) was adversely affected when the DS1620 temperature sensor chip was changed going from rev D to rev E. _______________________________________________ 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.
