EEVblog #235 – Rubidium Frequency StandardPosted on January 14th, 2012 4 comments
What’s all this Rubidium Frequency stuff anyhow?
Dave got an FE-5680A Rubidium frequency standard on ebay. How do they work?, and how does it compare to a regular crystal oscillator, a DTCXO, or an oven stabilised oscillator?
And I thought my Lpro 101 was cheap.
Thank you for the hint, at these prices I immeadetly had to buy one.
I also have a Gps locked Rbidium source from Ebay, but I am not sure if that is more stable than the Lpro 101. Furthermor I do not have the equiment to test the stability. If you have any ideas how to test the stability of an oscillator it would make a great tutorial.
Phase noise measurements would be interesting also.
The component on the quartz could be a PTC, intended for stabilizing the XTAL in temperature. (would explain the foam).
Or even more clever, could it be a heating rresistor for using the temperature for “pulling” the quartz as a VCXO ?
Concerning freq references, it would be also clever to avoid the rubidium, and to lock a 10 MHz VCXO on a GPS pps output… advantage : the same uC cold also be used as a freq. meter.
the acronym for crystal ovens actually is OCXO. A TCXO compensates for temperature variations while in a OCXO an oven keeps the crystal at a constant temperature.
After watching your video i bought the same FE-5680A Rubidium frequency standard and took some pictures with the thermal camera from work.
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