Hi I think there are two somewhat independent things flowing through this thread. The first is - what is the real minimum voltage for this or that level of operation. The second is - what is the voltage for *best* operation.
Every time I've been down this road before with an Rb, the answer to "what's best" has been a well regulated supply at the minimum specified input voltage. Varying the supply always seems to impact something and regulating supplies is easy these days. Bob -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of ewkeh...@aol.com Sent: Friday, January 20, 2012 8:01 AM To: time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A Voltage tolerance Starting Sunday I will do some voltage tests, giving up on aging test, nine weeks is long enough. I will se if the next one is as good, how ever I do not understand all the talk about running it at a lower voltage. Loosing regulation will definitely impact performance. I have not analysed my unit but a 13.3 V LDO was reported. In my opinion that says what the lower limit is based on sufficient margin for that regulator. What is wrong with 15 Volt? I am running the unit right out of the switcher no extra filtering and I can say based on my tests that it is good to 1 E-12. I also se a 4 Hz loop that will be there with any kind of regulation. That is why I will include a clean up OCXO with a 100 second analog filter. That OCXO will get special attention in its supply voltage regulation. Starting out with 15 Volt gives me enough head room. I am using a $ 10 12 V 2 A switcher cranked up to 15 V. Bert Kehren In a message dated 1/20/2012 7:43:16 A.M. Eastern Standard Time, n...@verizon.net writes: It is not surprising that many of these units work alright below their specified voltage. I would imagine that the internal regulators, in addition to dropping voltage, are also there to keep voltages stable, and thus help with unit stability. So, a unit may work fine, and be able to meet stability specs, when operated slightly below the 15 volts, PROVIDED that that lower input voltage is provided by a stable, regulated supply. If I were the manufacturer, I would not want to have to rely on the supply being perfect, I would want to do my own regulation as they have. These are used in a system where the power supply drives many items and there are voltage drops due to wiring, backplanes, traces, etc as well as variations due to load changes. You may be able to have one unit work fine slightly below spec'd voltage, but if you do that in a system or with an unregulated supply and all bets are off. Give the unit decent power within its specified input range and then that's one thing you don't have to worry about further. Peter On 1/20/2012 6:09 AM, Rob Kimberley wrote: > I've had one of mine running on a bench supply for about 2 days now. Have > just tried turning the voltage down, and things started to get unstable at > around 12.5V. It didn't drop out of lock however until about 9V. > > Rob Kimberley > > -----Original Message----- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Peter Gottlieb > Sent: 20 January 2012 04:16 > To: time-nuts@febo.com > Subject: Re: [time-nuts] FE-5680A Voltage tolerance > > When I got my first unit I hooked it up to my protoboard power supply which > is rated at 15 volts 0.5 amps and 5 volts 1 amp. I was annoyed that it took > about > 10 minutes to lock up until I realized the 15 volt supply was down near 11.5 > volts. Oops. Substituting my small B&K bench supply (good for up to 3 > amps) resulted in a lock in under a couple of minutes. Perhaps my unit's > internal adjustments are still just about right. It would be nice to get > the alignment procedure for the thing, but I suppose, fat chance of that. > > Peter > > > On 1/19/2012 6:45 PM, gonzo . wrote: >> Experiment for the day. >> I thought I'd follow Dons quote and see how tolerant my unit is. >> My benchmark is at 15.5V it locks in about 3min. >> I backed off the supply to 10.8V and the lock time (from cold) is 8min. >> >> I thought this was interesting given several people report they are unable > to get a lock when running lower voltage. >> ian >> >> _______________________________________________ >> 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. >> >> >> ----- >> No virus found in this message. >> Checked by AVG - www.avg.com >> Version: 10.0.1416 / Virus Database: 2109/4754 - Release Date: 01/19/12 >> >> > _______________________________________________ > 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. > > > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 10.0.1416 / Virus Database: 2109/4754 - Release Date: 01/19/12 > > _______________________________________________ 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.
