OK, I'll study the PRS10 manual. On Sat, Mar 31, 2012 at 3:10 PM, Erno Peres <erniepe...@aol.com> wrote:
> > Hi Ulbrich, > > Sorry but not everybody a digital and/or a professional guru... can you > please be a more specific.... namely to show us the pre filter and other > circuit....if you do not mind. > Understand that the key point is the PLL or the phase comparator > circuit.........if you want to build you own GPS-DO..... > > Many thanks and best regards, > > Ernie. > > > > > -----Original Message----- > From: Ulrich Bangert <df...@ulrich-bangert.de> > To: 'Discussion of precise time and frequency measurement' < > time-nuts@febo.com> > Sent: Sat, Mar 31, 2012 2:53 pm > Subject: Re: [time-nuts] CW12-TIM vs M12M and the world > > > Bert, > sometimes a manual can be a true treasure chest! Just download the PRS-10 > anual at > http://www.thinksrs.com/downloads/PDFs/Manuals/PRS10m.pdf > and find starting on page 13 the complete instructions on how to build your > wn GPSDO. A basic knowledge of math, programming and control theory is > eeded to understand the manual but then: It works. I have constructed my > own DIY GPSDO on the base of the information that I have found there, > ncluding the pre-filter. > Best regards > lrich > > -----Ursprungliche Nachricht----- > Von: time-nuts-boun...@febo.com > [mailto:time-nuts-boun...@febo.com] Im Auftrag von ewkeh...@aol.com > Gesendet: Samstag, 31. Marz 2012 13:46 > An: time-nuts@febo.com > Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world > > > Ulrich > can you tell us more about your pre filter? > Thank you > Bert Kehren > > > In a message dated 3/31/2012 6:23:49 A.M. Eastern Daylight Time, > df...@ulrich-bangert.de writes: > > Thomas, > > > Has anyone compared the M12M to the M12+? > > I have done some measurements on the M12+ with typical > results as shown in > > http://www.ulrich-bangert.de/M12Performance.jpg > > The red line is the raw phase data of the M12's PPS against > a PPS derived from a local FRK-L rubidium. Note that you do > not observe an overall difference frequency (and a resulting > drift in phase) because the FRK-L is disciplined by the GPS. > The blue line is the sawtooth corrected phase data and it > becomes immediatly clear HOW IMPORTANT applying the > correction is. The yellow line show you what happens if the > sawtooth corrected phase data is sent through a pre-filter > (lowpass with 1/3 the time constant of the > main > pll loop) before entering the loop itself. That is something > that I learned from the PRS-10 manual. You may decide on > your own which data you would > like > to work on in a GPSDO. > > Best regards > Ulrich Bangert > > > -----Ursprungliche Nachricht----- > > Von: time-nuts-boun...@febo.com > > [mailto:time-nuts-boun...@febo.com] Im Auftrag von Tom Knox > > Gesendet: Freitag, 30. Marz 2012 22:19 > > An: Time-Nuts > > Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world > > > > > > > > Has anyone compared the M12M to the M12+? > > Thanks for all the input, it is really appreciated. > > best wishes; > > Thomas Knox > > > > > > > > > CC: time-nuts@febo.com > > > From: saidj...@aol.com > > > Date: Fri, 30 Mar 2012 09:53:17 -0700 > > > To: time-nuts@febo.com > > > Subject: Re: [time-nuts] CW12-TIM vs M12M and the world > > > > > > Hello Ed, Azelio, > > > > > > We should also compare the same parameters. Sawtooth error > > of the m12+ > > > of +/-25ns is not its standard deviation, it's max/min. > > Compare that > > > number to your 30ns max/min measurement on the 5372a. > > > > > > Standard deviation of the m12+ is around 2ns with > correction. That > > > needs to be compared to the 5ns you measure on the 5372a > as that is > > > the best performance you will get from the CW12. Yes the > > uncorrected > > > 1pps of the m12 is worse, but it is designed to be used with > > > correction. So in the end the m12m still performs better > than the > > > CW12. > > > > > > Bye, > > > Said > > > > > > Sent From iPhone > > > > > > On Mar 29, 2012, at 1:56, Azelio Boriani > <azelio.bori...@screen.it> > > > wrote: > > > > > > > We (that is my company) use the CW12-TIM (NMEA version) > > and its PPS > > > > wonders as usual, nothing different from a uBlox LEA-5T > > or the M12M. > > > > > > > > On Thu, Mar 29, 2012 at 9:32 AM, Hal Murray > > > > <hmur...@megapathdsl.net> wrote: > > > > > > > >> > > > >>>> The sawtooth error on the Motorola M12+ is about +/- > > 25ns, while > > > >>>> the CW12-TIM has a sawtooth error of +/- 2 ns, so > > correcting for > > > >>>> the sawtooth error is not as critical with the CW12-TIM. > > > >> > > > >>> The first claim > > > >>>> The sawtooth error on the Motorola M12+ is about +/- 25ns > > > >>> is correct but are you absolutely sure that the > second claim is > > > >>> correct too????? > > > >> > > > >>> It would mean a factor >10 improvement of the CW12-TIM > > against the > > > >>> M12 > > > >> which > > > >>> is hardly believeable. > > > >> > > > >> The 25 ns probably comes from period of the the free > > running clock > > > >> they are using. It doesn't seem unreasonable to me > to get 10x > > > >> better if they use a GPSDO for the local clock so they > > can get the > > > >> PPS edge right where they want it. > > > >> > > > >> > > > >> > > > >> -- > > > >> These are my opinions, not necessarily my employer's. I > > hate spam. > > > >> > > > >> > > > >> > > > >> > > > >> _______________________________________________ > > > >> 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. > > > > _______________________________________________ > > 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. > > ______________________________________________ > ime-nuts mailing list -- time-nuts@febo.com > o unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > nd 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.