Hal Murray wrote: >>>I assume it's a software bug/feature. The problem is drift/wander >>>in the offset. The offset changes too slowly for normal >>>jitter filters to work on it. >>> http://www.megapathdsl.net/~hmurray/ntp/GPSSiRF-off.gif > > >>connected via serial/nmea or pps? > > > Direct USB. > > I have another one (using the SiRF chips) that is serial > via a serial-USB adapter. Same thing. There is a good chance that the direct USB thingy has the serial2USB converter just integrated ( replacing the rs232 levelshifter ). > > > >>that looks like some beat frequency effect. >>But it is much too slow/time too big >> to be sender and/or receiver uart clocking. > > > Yes. But I don't think it's a USB problem. I get much better > results with a Garmin GPS 18 USB. (Of course, what I don't know > about USB could fill ...) I had my fingers in USB recently, but ..
> Hmm, you get one sentence per second? I will have to read up if the usb2serial ics have some kind of fifo included ( and enabled or not ). This could be an explanation. uwe _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
