[time-nuts] Thunderbolt oven / non-stable operating temperature
holrum at hotmail.com
Wed Dec 12 02:35:34 UTC 2012
Although the Trimble oscillator has superb phase noise performance, it has TERRIBLE temperature sensitivity. It appears to be a single oven oscillator, not a double oven. The PWM'ed fan temperature control implemented in Lady Heather effectively makes the unit a double oven. Also, by stabilizing the temperature of the rest of the tbolt electronics and power supply (if included in the temperature controlled box) you get additional performance out of the unit. Some testing indicates that a temperature stabilized tbolt/power supply can improve the performance by an order of magnitude (around 30% of that is due to issues outside of the oscillator can).
And yes, Lady Heather can control the Tbolt DAC. There is a PID controller in there for controlling the DAC (based upon the 1PPS error signal, if I remember correctly... it could be the OSC error signal).
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