Hello Dave, as some folks have already mentioned here, the best solution for you will depend on your specific requirements in terms of how much warmup time you have before GPS is gone, and how much drift your solution can handle. The PRS-10 is a good unit, but requires cooling, a large amount of power, only has a single 10MHz and 1PPS output, and it has a somewhat noisy output in terms of phase noise and short-term-stability. It also costs about $1500, is quite large, and does not provide a GPS receiver, nor one especially optimized for timing. You may want to look at the Fury or FireFly-IIA GPSDO units, these are lower cost, include the complete GPS sub-system, achieve performance similar to the PRS-10 after sufficient warmup, are much smaller, lower power, the FireFly-IIA has a built-in isolated distribution amplifier, and don't have an Rb lamp life limitation. Typical Fury DOCXO units can achieve better than 1us drift over 24 hours after they have fully stabilized, which is better than many Rubidium references. If you are looking for drift in the <10us range per day, you will need a double oven SC-cut OCXO. You didn't mention if your application was airborne, in that case you may need a low-g sensitivity oscillator to avoid loss of short term stability and increased phase noise due to aircraft vibration and acceleration. Rubidiums are especially sensitive to airborne vibration such as caused by Turboprops, Rotorcraft, etc. Without having your specifications for the warmup time, thermal changes, and the desired drift, it is difficult to say if a single oven, double oven, Cesium, or Rubidium based unit would work for you. Lastly, unless you are underwater or under-ground, GPS should be available with a modern, good jamming-resistant receiver, and if it is a modern GPSDO will perform as well or better than a modern Rb. bye, Said In a message dated 11/19/2010 14:43:43 Pacific Standard Time, li...@rtty.us writes:
> > I had assumed that a Rubidium oscillator would give me the best stability > over the course of 8-12 hours. Obviously a Cesium would be better but those > are impractical due to cost and power constraints. I've begun evaluation of > a Rb oscillator but now I'm being told by some people that a good DOCXO is > likely to give me similar medium term stability (with obviously better > short-term stability). > > Anyone here have thoughts on this? Obviously I'd rather go with a DOCXO for > cost and power reasons if there's no performance benefit to be had using a > Rb osc. The Rb unit I'm testing (http://www.thinksrs.com/products/PRS10.htm) > seems to perform well but I am interested in hearing others' thoughts. > > Thanks, > > Dave > > ---------------------- > > Dave Jabson > Systems Engineering Manager > Quasar Federal Systems > 5754 Pacific Center Blvd, Suite 203 > San Diego, CA 92121 > 858-412-1706 > www.quasarfs.com > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.