Hi I think you will find that the noise floor of the ADF4107 (dividers and phase detector) is a bit higher than -150 at 100 Hz offset at 10 MHz. It should get you past the -120 level though. That's still much better than you are seeing.
Indeed -120 is not what figure 15 on page 8 of the specification would imply. I'm sure that the figure is technically correct. It's just not showing the complete picture. Bob -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Christophe Huygens Sent: Tuesday, March 09, 2010 12:28 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Realistic Tbolt phase noise Hi, I am using an ADF4107 and a Crystek resonator, with a LBW of a few 100 Hz. It behaves perfect outside the loop, but inside the loop it is too noisy (not too important for my application, but just curious). I ll try to measure the Thunderbolt directly at 10Mhz, but the my HP 11729C needs some mods for this. Christophe On 09/03/10 18:21, Bob Camp wrote: > Hi > > How are you multiplying it to 1 GHz and checking it? > > I've seen multipliers that have issues beyond about -130 at 100 Hz. It's not > common, but it can happen. > > ------------------ > > The supply provided by TAPR is a pretty basic unit. It would not surprise me > if some were better than others. They also may work better on US mains > voltage than they do on international voltages. I would rig up another > supply and see what happens. That would at least rule out the supply as an > issue. > > In a previous post the idea of putting a 7805 and 7812 regulator on the > TBolt came up. If you have +14 available that seems like the best thing to > try. > > Bob > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of Christophe Huygens > Sent: Tuesday, March 09, 2010 7:50 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Realistic Tbolt phase noise > > This is with the power supply as provided by TAPR so should be ok. > > Xtof. > > > On 09/03/10 13:44, Bob Camp wrote: > >> Hi >> >> Power supply noise would be the first thought. >> >> Next up would be grounding inside the Thunderbolt (card to case, >> > connectors to case). > >> Bob >> >> >> On Mar 9, 2010, at 7:32 AM, Christophe Huygens wrote: >> >> >> >>> Hi, >>> >>> I noticed several vendors on Ebay have the t-bolt on sale. >>> >>> However, the once showing their own PN plots seem to get only >>> -115, -120 dBc/Hz at 100Hz. Yet, >>> http://www.leapsecond.com/pages/tbolt/noise.htm seems >>> to have mucht better results: up to -150 depending on >>> power supply. >>> >>> By multiplying to 1GHz I also seem to be getting something >>> like -75 or - 80 rather than -110. >>> >>> Any thoughts? >>> >>> Christophe >>> on4iy >>> >>> >>> >>> _______________________________________________ >>> 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. >>> >>> >>> >> _______________________________________________ >> 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. >> >> > > _______________________________________________ > 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. > > > > > _______________________________________________ > 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. > _______________________________________________ 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. _______________________________________________ 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.
