>Q) Can you explain again why you are thinking this? A) Yes, Short answer is I do not think Tom's graph's have finished analyzing the data. As soon as I can get a copy of the raw data so that I can check out my claims in a simulator, I'll show you why I say that.
WarrenS ******************** ----- Original Message ----- From: "Ulrich Bangert" <[EMAIL PROTECTED]> To: "'Discussion of precise time and frequency measurement'" <[email protected]> Sent: Saturday, December 06, 2008 9:23 AM Subject: Re: [time-nuts] Analog or Digital GPSDO? > Warren, > > I may be teriible wrong but I understand Tom and his data so that PPS > and 100 Hz have the SAME performance (what I had expected) with the PPS > being able to be improved by the sawtooth correction. Attached are some > seconds of data from my GPSDO which second Tom's measurements as far as > the PPS is concerned. > >> All else being equal, Tom's data says to me that a simple analog front > end design when >> combined with a microprocessor is able to provide a better performing > GPSDO >> than any digital only unit that is using just the 1PPS. > > Can you explain again why you are thinking this? Tom's claim is: > > For all tau beyond 1 second, the ADEV of the 100 Hz output exactly > matches the ADEV of the 1PPS output. > > So, it does not matter whether PPS or 100 Hz are used, it is a question > of the loop time constant only, which must be the same for both. > > Best regards > Ulrich > >> -----Ursprungliche Nachricht----- >> Von: [EMAIL PROTECTED] >> [mailto:[EMAIL PROTECTED] Im Auftrag von WarrenS >> Gesendet: Samstag, 6. Dezember 2008 15:57 >> An: Discussion of precise time and frequency measurement >> Betreff: [time-nuts] Analog or Digital GPSDO? >> >> >> >> Here is a posting meant to start a debate between open minded >> freq-nuts. It is inspired by Tom's latest posting at > http://www.leapsecond.com/pages/m12-adev/ > > All else being equal, Tom's data says to me that a simple analog front > end design when > combined with a microprocessor is able to provide a better performing > GPSDO > than any digital only unit that is using just the 1PPS. > It would appear that the analog front end can be as good and even better > > than using the sawtooth correction data. > > I may be a bit pregidous toward analog because I have been using > analog only sub ns tracking of the GPS error signal for a long time. > > What analog or digital can not address is any of the issues concerning > non carrier phase receiver limitations. > so I'd like to assume for this discussion that the GPSDO is using a > Motorola Oncore type > of receiver with position hold capability. > > A different but related question is, does or would using some form of > waas help a GPSDO? > > Have fun with it, > WarrenS > > > > _______________________________________________ > 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.
