[time-nuts] Navsync CW12 - More Info

Ed Palmer ed_palmer at sasktel.net
Thu Jan 5 19:29:00 UTC 2012


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_palmer at 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 at 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 at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



More information about the time-nuts mailing list