Hi The sweep range on the LPRO's is very similar to the sweep range on the FE's. They both run the VCXO over a very wide range compared to the width of the Rb resonance. They both also have to accommodate VCXO temperature performance and aging.
Bob -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Albertson Sent: Wednesday, February 15, 2012 5:34 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] FE-5680A Question On Wed, Feb 15, 2012 at 2:17 PM, Bob Camp <li...@rtty.us> wrote: > Hi > > If you look at an LPRO or FRS or any of the other brands of Rb's their sweep > is very different. They don't spend very much time at the ends of the sweep > at all. It's pretty much a triangle wave sweep up and back sort of thing. > They don't seem to care weather they catch the lock going high to low or > going low to high. The rate of the sweep is *much* slower than what FE is > doing on these units. Since there isn't a "brain" in most of them, there's > no pattern watching stuff there. They just look for a lock signal (amplitude > out of the detector) and stop sweeping when they see it. That method requires that your sweep in so narrow that it can't catch any other adjacent spectral lines or "dips" in the light. FEI may have found a way to use a much wider sweep by havinf a "brain" able to know the fauslt dips from the one it wants. The "ends" that appear dead might be where the software analyses the data from the previous sweep. I doubt the little uP can mulitask. The uP is doing "something" when it is not sending commands to the DDS to cause the sweep. My understanding of a Rb physics package is that you get a "forest" of lines and only the one is the "good" one. Chris Albertson Redondo Beach, California _______________________________________________ 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.