OK, thank you. On Thu, Jan 5, 2012 at 8:29 PM, Ed Palmer <ed_pal...@sasktel.net> wrote:
> Do you mean the reference oscillator for the 5372A? That was the internal > 10811 OCXO. Over a 1000 sec. run, drift wouldn't have any affect on these > numbers. > > Ed > > > On 1/5/2012 12:54 PM, Azelio Boriani wrote: > >> 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. >> >> > _______________________________________________ > 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.