Chris Albertson <albertson.ch...@gmail.com> wrote: > I think you can do just fine without GPS and GPSDXO oscillators and > the like. NTP over the Internet is an order of magnitude better then > you need.
No, I really don't want anything NTP-based. Or let's put it another way: part of my objective is to set up a stratum 1 NTP server that would serve my UTR timescale to the public Internet. By definition a stratum 1 NTP server does NOT use another NTP server as its reference. Look guys, I have thought it through and I really want to do it my way. Sure, it may be way overkill, but I still want to do it my way. The reason I have started this thread on time-nuts (rather than the leapsecs list for example) is not to argue philosophies, but to solicit advice on the choice of specific GPS receiver / GPSDO types. I'm still looking for that. Forget about my eccentric choice of output timescale and everything else in this thread. The part below is what I am soliciting advice for: I desire to build a circuit that generates an interrupt every millisecond, and have every 1000th interrupt correspond to the second boundary in "official" time scales such as UTC, TAI and GPS (which all agree on where the second boundaries should be). Forget for the moment why I want this circuit, let's say I just do. THIS is the part I am seeking advice on, nothing else. Do I need a plain GPS receiver or a GPSDO? From what I understand, non-DO GPS units only put out 1 PPS, no 10 MHz, right? Basically I would then have to take the 1 PPS input and somehow fill in the milliseconds in between. If I do it myself, it seems to me that I would be reinventing a GPSDO, but perhaps I'm wrong on that. I don't need the 1 PPS to be phase-locked to 10 MHz, instead I want the 10 MHz to be frequency-locked to 1 PPS. I don't care if there is no guaranteed phase relation between the two signals as long as *on average* there will be 10 million cycles of 10 MHz between successive 1 PPS pulses. Nothing bad will happen if any given interval between 1 PPS pulses features a few cycles too few or a few cycles too many on the 10 MHz, as long as there is no long-term frequency drift between the two signals. In other words, I want to be able to clock my circuit from the 10 MHz, catch the 1 PPS once, and then depend on every subsequent 1 PPS being within a certain fixed window of where I would expect it to be. Which GPSDO do you guys think would do this job best? Also what happens to the GPS receiver's serial port in a GPSDO configuration? A standard GPS receiver has a 1 PPS output and a serial port, right? The serial port transmits a message every second saying what actual time the next 1 PPS corresponds to, right? And one can send commands to that port to change the receiver's configuration, right? Such as switching between leap-second-corrected and non-LS-corrected output, right? What happens to this serial port in a GPSDO configuration? Does it pass through GPSDO firmware? How much direct access to the actual GPS receiver is still allowed, or none? These are the kind of things I'm wondering about; I don't need to be told to use NTP on a PC instead. MS _______________________________________________ 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.