Re: [time-nuts] FEI 405B oscillators
Gerhard, does not sound right, Tom did an extensive evaluation, steps in 6.6 E-15 at 15 MHz. Our best GPSDO.Am out of town back Tuesday have extensive info on my PC need to get off listBertSent from my Galaxy Tab® A Original message From: Gerhard Hoffmann Date: 7/6/19 11:58 PM (GMT-05:00) To: Discussion of precise time and frequency measurement Subject: [time-nuts] FEI 405B oscillators Hi,I have one of these FEI405 oscillators from this list auction 4 years ago.While it dives nicely down deep into E-13 land over some seconds, it only delivers -2.5 dBm output powerand has a lot of phase noise and spurs far out. That does not look healthy.Is there a real data sheet out there in the wild, or has someone even re-engineered this thing?If you google for it, you get links to Fender guitar bags, fertilizers and electron microscopes,but nothing on oscillators apart of the time nuts thread from 4 years ago.If the data sheet really says -2 dBm, then I could get rid of the spurii and life would be OK.Yes, I have found the Frequency Electronics web site, but it seems they deny parenthood.Gerhard___time-nuts mailing list -- time-n...@lists.febo.comTo unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.comand follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Question about the PLL of Trimble Thunderbold
I have only worked with the GPS part of the KS system but some time nuts may be able to explore the use of the second half and they are available at areasonabble price Bert KehrenSent from my Galaxy Tab® A Original message From: Bob kb8tq Date: 10/30/18 5:43 PM (GMT-05:00) To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Question about the PLL of Trimble Thunderbold HiThe Trimble Thunderbolt does not have a 1 pps between the GPS chips and the OCXO. It makes the link between the two portions of the system in a different way than the typical GPSDO. It uses the OCXO as the clock reference for the GPS chip set. It then uses phase data on the received signal to “lock” the OCXO. The whole process is very much unique to the Trimble product line. To do a mod and extract a PPS, you would need to find a GPSDO based on something like a uBlox chip set or module. You potentially *could* cut a trace and inject a new PPS. For most devices, you would also have to generate the proper “status” messages that go from the uBox (or other module) to the control loop processor. Some of these messages are in response to specific queries. Others are generated automatically. Bob> On Oct 30, 2018, at 4:22 PM, Ferran Valdés wrote:> > Thank you all for your answers,> > > > I do have an additional question. Did anybody install an external 1PPS/10MHz input to the Trimble Thunderbolt board ??> > With the idea that, when the adjustment loop is deactivated, an external signal can be supplied to the Thunderbolt, and the Time Interval circuit could show the difference in between this signal and the feedback of the VCO.> > > > > > @ Bob kb8tq> > > > The aim of this project has no commercial purposes and the project itself is to develop the algorithm which will be in charge of adjusting the clocks. Also is yet to be determined the information that will be exchanged in between nodes in order to achieve as accurate synchronization as possible.> > > >> Hi> >> Unfortunately there are no ?stock? boards to do this sort of thing. If this is a commercial> >> requirement, there are companies who do this kind of thing on a custom basis. Figure on> >> a few thousand dollars NRE and a minimum order of a few hundred to get somebody> >> interested. At the ?couple ps? level, the NRE may be a bit above the few thousand> >> level. Also expect to supply a full spec requirement when you go shopping ?.> >> Bob> > > > @Attila Kinali> > > > > > Could you please share a link/name of the paper ? All information is welcome !> > > > The method that you've developed, synchronizes 4 local clocks in reference to one, or they keep a certain difference all together in between themselves ?? Which FPGA are you using ?> > > >> I have something ready, that can synchronize 4 independent clocks> >> to eachother at the 180ps level, limited by the FPGA based TDC.> >> The current incarnation does not allow for an external clock source> >> to syncrhonize to, but that should be easy to add. That is, if you> >> don't mind using some half-finished we-have-published-a-paper research> >> tool.> > > > Lets say that the objective is to reach 50ps. Of course is not an easy to achieve goal, but that's the purpose of the project, to try to achieve as best synchronization as possible within an strict time frame.> > Part of the project will consist in taking into account the propagation delay in between the medium used, be it a cable, fiber or radio link. Still to be determined, but most likely it will be a cable.> > > > Nice tips on the cables, I will do a documentation research to learn further.> > > >> But going to ps level of synchronization, especially if you mean <10ps,> >> is not going to be easy. There are not many ways to measure pulses> >> with this accuracy. If you know what you are doing, about 1-3ps RMS is the> >> practical limit you can achieve, more likely it'll be in the order of 10-30ps,> >> for a one-off design. Also keep in mind that ~2mm of cable is already 10ps of> >> phase shift. Ie you will need to calibrate your cables as well. Cables,> >> which are of course low dispersion and low temperature coefficient cables.> >> The dispersion is important so that your pulse remains a sharp pulse.> >> through the cable and doesn't come out grabled as a weird wave packet,> >> Quite counter-intuitively, limiting the slew rate might help with this.> >> The low TC is important if there is any distance between the two> >> oscillators. Otherwise you can get up to several ps per ?C temperature> >> change and meter cable length for run of the mill cables. If you have> >> PTFE cables, you also want to keep them well above 25?C or well below 15?C,> >> for the same reason.> >> Attila Kinali> > > > > > > > @Tom Van Baak> > > >> I'm glad you mentioned your requirements. Note that time synchronization at a >"ps level" is 3 to 4 orders of magnitude beyond what the typical
Re: [time-nuts] OCXO Board
I took delivery last Thursday of 8 10X10 boards 10 each 2 days DHL from China total cost $ 86 Bert Kehren Sent from my Galaxy Tab® A Original message From: Bob kb8tq Date: 10/26/18 4:21 PM (GMT-05:00) To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] OCXO Board HiI think what is needed is somebody to stand up and say “ok, I’ll handle all theordering and shipping stuff”. No, that somebody is not me …. sorry about that. There are a *lot* more board designs than just this one floating around. This couldturn into a fairly complex little enterprise. If the first boards really are “well under $1 each” sort of boards (and I’m quite sure they are),doing this one board at a time is going to be …. errr… nutty. I’d suggest that something like groups of 5 (or maybe even 10 if then are < <. $1 is likely the smallest rational increment to play with. When shipping is more than the stuff in the envelope … that’s silly. Since you pretty much always see people coming back a while later wondering if they can get more boards on anything like this, getting a few extras is nevera bad idea. So who has way too much time on their hands and *really* likes driving to the post office?Hmmm …. not many hands raised. Probably a good idea to include the thought that there *should* be something in the deal for the poor person doing all the work. I’d saythey should get at least as much as the post office does …. just saying …..Bob> On Oct 26, 2018, at 3:35 PM, Patrick Murphy wrote:> > Not to be a "me too", but I think there will be some interest for this> board. Including a couple for me. :-)> > -Pat (KG5YPQ)> >> Dave wrote:>> Yep!! Count me in for a few also!! maybe 4 or 5...>> >> Dave M> >> Wes wrote:>> I'm not up to doing the whole project, but I would certain be>> interested in 2 or 3 boards for sure.>> >> Wes Stewart N7WS>> >> On 10/26/2018 5:51 AM, Bob Martin wrote:>>> Bert,>>> >>> That looks like a useful board. Certainly some of the oscillators>>> I'm giving away would fit nicely on it. Since it looks like a two>>> layer board, a quick check at pcbway.com puts the cost at $.79>>> apiece at the 100 quantity exclusive of shipping.>>> >>> Best,>>> >>> Bob Martin>>> >>> On 10/26/2018 4:17 AM, ew via time-nuts wrote: There recently was a request for an OCXO board. I did a layout, see attached and had Corby do his usual QC test. If some one is interested to make boards and maybe sell to other time nuts please contact me off list and I will get you code and possible suppliers. Board does not have an amp but could be added, if so, please advise, what should be added. Regardless what the direct output will remain Bert Kehren >> > ___> time-nuts mailing list -- time-nuts@lists.febo.com> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com> and follow the instructions there.___time-nuts mailing list -- time-n...@lists.febo.comTo unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.comand follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] OCXO Board
I have added OSA 8663 was not easy no more Please BertSent from my Galaxy Tab® A Original message From: Patrick Murphy Date: 10/26/18 3:35 PM (GMT-05:00) To: time-nuts@lists.febo.com Subject: Re: [time-nuts] OCXO Board Not to be a "me too", but I think there will be some interest for thisboard. Including a couple for me. :-)-Pat (KG5YPQ)>Dave wrote:>Yep!! Count me in for a few also!! maybe 4 or 5...>>Dave M>Wes wrote:> I'm not up to doing the whole project, but I would certain be> interested in 2 or 3 boards for sure.>> Wes Stewart N7WS>> On 10/26/2018 5:51 AM, Bob Martin wrote:>> Bert, That looks like a useful board. Certainly some of the oscillators>> I'm giving away would fit nicely on it. Since it looks like a two>> layer board, a quick check at pcbway.com puts the cost at $.79>> apiece at the 100 quantity exclusive of shipping. Best, Bob Martin On 10/26/2018 4:17 AM, ew via time-nuts wrote:> There recently was a request for an OCXO board. I did a layout, see>>> attached and had Corby do his usual QC test.> If some one is interested to make boards and maybe sell to other>>> time nuts please contact me off list and I will get you code and>>> possible suppliers.>> Board does not have an amp but could be added, if so, please>>> advise, what should be added. Regardless what the direct output>>> will remain>> Bert Kehren___time-nuts mailing list -- time-n...@lists.febo.comTo unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.comand follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Programmable clock for BFO use....noise
Good choice Bert Kehren Sent from my Galaxy Tab® A Original message From: Gerhard Hoffmann Date: 9/16/18 6:30 PM (GMT-05:00) To: time-nuts@lists.febo.com Subject: Re: [time-nuts] Programmable clock for BFO usenoise Am 16.09.2018 um 23:11 schrieb Attila Kinali: > On Sun, 16 Sep 2018 22:08:19 +0200 > Gerhard Hoffmann wrote: > >> I'm also not a fan of using slowish, slew-rate challenged logic as a >> replacement >> for a low pass. When I want a low pass, I make it from nice, >> time-invariant RLC. > Unfortunately, using a low pass after the divider will not > prevent the down-mixing. The down-mixing happens as an inherent > property of digital circuits. Any filtering you do afterwards > will be too late. If you want to have low noise, then the only > way is to produce a non-square wave signal. Or in other words: > use a divider built from harmonic mixers*. Why do you assume that slew-rate limited mixers are any better than mixers with an ultra-short analog time window for doing mess? We should sort that out offline, we are just 20 miles apart? I propose the Zwickel pub in Dudweiler; I'm there with the mostly emerited Fraunhofer people on Friday evenings now & then. :-) :-) :-) > * That is, if you don't like Λ-dividers or DDS I do like DDS, and I don't see a reason for the D/A converters in front of the mixers. D/A converters remove the fun when you can just instantiate a multiplier. Cheers, Gerhard ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Programmable clock for BFO use....noise
The question was deviding a Rb 20 MHz to 10 that is easy to but how much effort is dependant what it is used for and that in turn determines what to use on the input. We have 4 choices depending on the requirementBert Sent from my Galaxy Tab® A Original message From: Attila Kinali Date: 9/15/18 8:34 AM (GMT-05:00) To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Programmable clock for BFO usenoise Hoi Bert, On Sat, 15 Sep 2018 11:09:18 + (UTC) ew via time-nuts wrote: > What about the application and the trigger circuit Sorry, I don't understand what you mean. Attila Kinali -- The bad part of Zurich is where the degenerates throw DARK chocolate at you. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] NIST
Thank you Magnus I focused on 2017 because of the changes but do not understand because it is a divisionBert Sent from my Galaxy Tab® A Original message From: Magnus Danielson Date: 8/10/18 3:11 PM (GMT-05:00) To: time-nuts@lists.febo.com Cc: mag...@rubidium.se Subject: Re: [time-nuts] NIST Bert, The closes I come is this, burried in the line of Funamental Measurements: https://www.nist.gov/fy-2019-presidential-budget-request-summary/budget-tables It doesn't get more detailed than that. The T work is relatively small group in the big NIST. Cheers, Magnus On 08/10/2018 08:29 PM, ew via time-nuts wrote: > > NIST total budget for 2017 was close to 965 Million, I was curios trying to > find out what the Time and Frequency Division portion was. No Luck. Does any > one know?Thanks Bert Kehren > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
