Hi Steve: There is no Rubidium oscillator. See the block diagram at: http://www.prc68.com/I/PRS10.shtml#BlkDia The amount of light passing through the Rb cell is used to steer a quartz oscillator. In the case of the PRS10 it's an ovenized oscillator that's an improved and smaller version of their SC10.
Have Fun, Brooke Clarke http://www.prc68.com/P/Prod.html Products I make and sell http://www.prc68.com/Alpha.shtml All my web pages listed based on html name http://www.PRC68.com http://www.precisionclock.com http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Web Cam Steve Rooke wrote: > 2008/10/24 <[EMAIL PROTECTED]>: >> the jumps are very slow in their frequency change, so the crystal filters >> would just follow the frequency drift. I have seen these jumps take from a >> few >> seconds to 20 minutes or so. Of course in a Rb they would be compensated by >> the Rb pulling or pushing the crystal onto the proper frequency. > > But I'm not suggesting that the rubidium stage is used to discipline a > ocxo and then fed onto a xtal lattice filter, I meant that the > rubidium stage would go directly into the xtal lattice filter. This > way there is no xtal oscillator to jump off frequency. > >> Also, the additional crystals in the filter will very likely jump too, so I >> would expect the overall performance to actually get worse. > > If the jump is due to tiny physical effects on a crystal edge, as > previously described, I would doubt that every xtal would be exactly > the same wrt this and I very much doubt that all the xtals in a > lattice filter would jump at the same time and in the same way. This > type of filter works on the basis that each element suppresses signal > outside its centre frequency. If one xtal changes it's centre > frequency, all that changes is that the signal level at that stage > output drops (as in an off-tuned tuned circuit in a multi-stage filter > would do). Also the probabilities that every xtal would jump at the > same time would surely be very high and I'm not sure that using a xtal > in a filter circuit would be subceptable to this jumping in the same > way as using it in an oscillator circuit. > > Now if the jumps were caused by something like a cosmic ray, I would > expect that the xtal would just wobble off frequency rapidly and very > quickly go back to its resonant frequency. Using a multi-stage xtal > filter should circumvent this as the particle would have to physically > strike all the xtals in the filter on it's path. Physical arrangement > of the xtals in the filter would easily guard against that. > > If the jumps are caused by gravitational effects, it should be > similarly possible to design the filter the be less prone to these > affects by the orientation of the xtals. > > 73 - Steve _______________________________________________ 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.
