I never came to that conclusion. There is enough work out there with results. My comment was to that particular paper that did not measure up to the work Corby has been doing. Still trying to figure out the purpose of the posting. Bert Kehren In a message dated 4/29/2013 6:34:24 P.M. Eastern Daylight Time, bruce.griffi...@xtra.co.nz writes:
Since performance improves as the bandwidth of the "lamp" spectrum decreases its not unreasonble to suggest that a suitable laser source may improve performance further. The following paper (and theoretical considerations) indicate that your conclusions regarding the potential performance of a laser pumped rubidium standard are incorrect. http://tf.boulder.nist.gov/general/pdf/1219.pdf The addition of second harmonic traps tuned to the 2nd harmonic of the modulation frequency of the resonance interrogation signals should improve the performance considerably. Bruce ewkeh...@aol.com wrote: > > I am still sitting here trying to figure out the purpose of posting the > article on laser diode pumping of the Rb. One look at the data and it is > clear that Corby’s work far surpasses the data shown in the paper. All it does > is distract from Corb’s accomplishments. Lets be clear, Corby has opened > the door of H Maser performance for those that have a HP 5065A. Not all work > is done but a giant step has been accomplished, the challenge now is to > continue the work. In simple terms it gets down to keep the A/V slope from > turning upward. Work is going on off list to address some of the issues and > maybe some one is willing to contribute. But what the list at a whole can do > is contribute data as to HP 5065A performance. There are quite a few 5065A’s > out there but very little data besides HP spec. To better tackle the > flattening of the curve, aging, temperature sensitivity, barometric pressure > sensitivity and even humidity sensitivity has to be understood. It is > unrealistic to get past 1 E-13 unless this is understood and compensated for. Also > some of these parameters will vary from unit to unit and some degree of > tailoring to a particular unit has to be considered in the design. Some tests > have to be done by those members that have access to a Maser. > Also Corby found out that units with older A3 modules did not get the > performance boost but replacement of A3 did get the super performance. That > confirms my suspicion that there is room for work on frequency generation. PRS > 10 does a direct frequency generation. Somehow using the step recovery > diode as a mixer obviously works but is it optimum, or is there a better way > to generate the resonator frequency? What is key to get the best signal and > S/N ratio? > When previously mentioning aging control, concern was voiced as to getting > in to the HP 5065A. Corby’s work gets to the hart of the unit, the RVFR, > but Corby has gone four for four. Adding control will only move the two C > field wires to the analog board and using 30 mA from the unit. Unit can > easily restored to its original condition as far as frequency control is > concerned. > Obviously the RVFR is the big differentiator in the HP5065A and I know of > no commercially available unit that even gets close but once the work is > complete a look at a FRK may be in order, I doubt it will ever be as good, > but there is room for a filter and the physics part is considerable larger > than today’s units. Some other units may be using a filter but the physics > package is so small that compromises had to be made and the goal was more > cost than ultimate performance. > It is up to the list to turn this in to a Maser like performance with out > mortgaging your home. > Bert Kehren > _______________________________________________ > 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. _______________________________________________ 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. _______________________________________________ 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.
