Great, don't forget to specify what reference your measurements were made from (or did I miss anything from your posts?). We use the CW12 PPS for our GPSDOs.
On Thu, Jan 5, 2012 at 6:57 PM, Ed Palmer <ed_pal...@sasktel.net> wrote: > Okay, I've cooled off - a bit. The bottom line is that the 10 MHz output > of the CW12 isn't appropriate for what I wanted to do. Ah, the joys of > reading and understanding a spec sheet! > > But let's not throw out the baby with the bathwater. Although the 10 MHz > output has it's issues for typical Time-Nut applications, the 1 PPS output > is great. Here are some measurements that I've made over the past few > years on a few GPS receivers and a couple of GPSDOs. I measure 1000 > periods of the 1 PPS and look at the results. Every run gives somewhat > different results so I've shown some typical ranges. These measurements > were made with an HP 5372A. YMMV. > > Device .............. Std Dev (ns).... Range (max-min)(ns) ... Device Type > > Navsync CW12 ........ 4 - 5 .......... 20 - 25 ............... GPS Rcvr > Motorola UT+ ........ 40 - 55 ........ 95 - 110 .............. GPS Rcvr * > see below > Rockwell Jupiter .... 10 ............ 50 ................... GPS Rcvr ** > Motorola M12M ....... 10 - 15 ........ 40 - 60 ............... GPS Rcvr > > Trimble Thunderbolt . 0.4 - 0.5 ...... 2 - 4 ................. GPSDO > HP Z3801A ........... 0.3 ............ 2 ..................... GPSDO *** > > > * Most of my UT+ 'range' results were in this group, but there were a > few at 20 - 30. > ** Only one result. > *** Only one result. I need to do more testing on the Z3801A > > > As you can see, the Navsync CW12 is by far the best of the GPS Receivers, > but nowhere near as good as the GPSDOs. However, imagine using the CW12 to > discipline a good OCXO to build your own GPSDO. Or using it to discipline > a PRS10 Rubidium or X72 Rubidium oscillator. You can't do it with the 10 > MHz output, but the 1 PPS output is another story. > > Ed > > > > > _______________________________________________ > 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.