[time-nuts] u-Blox ZED-F9T block diagram or timing knowledge available here?

[jimlux]

On 1/6/20 6:25 PM, Bob kb8tq wrote:
> Hi
> 
> If you go back in the list archives, there is a lot of info on doing this and that with the
> F9P and the F9T. For a while, there was speculation that the price on them would come
> down quite a bit. So far that does not seem to be happening.


How to search archives effectively with Google.. "site:febo.com"





> 
> Bottom line is that both the F9P and F9T have roughly a +/- 4 ns sawtooth range. The
> sawtooth error correction information out of the device will take this down a bit, but not
> quite as far as some of us hoped.
> 
> Since both devices are dual band, you can easily post process the data against various
> services. I put out some plots suggesting a pretty good level of performance doing this.
> (sub nanosecond at short tau). I have not revisited the project since then.
> 
> As far as either device tagging an input to better than 4 ns …not so much. Same thing
> with the PPS doing better than that.
> 
> At the moment, the Furuno modules have the smallest sawtooth window that I know of.
> 
> Bob
> 
>> On Jan 6, 2020, at 8:56 PM, Tim S <tim.strommen at gmail.com> wrote:
>>
>> Hi, first time poster, just getting into the time rabbit-hole.
>>
>>     I'm looking at building my own 10MHz double-oven + Rubidium standard
>> for home-lab use, and I wanted to investigate GPS disciplining.  I read
>> some remarkable work using Jupiter engines and a simple N/1000 and PLL, but
>> with those receivers becoming much more outdated and higher precision GPS
>> receivers now fairly cheap - I thought I'd try something new from uBlox to
>> not repeat prior efforts.  I've gone all through every resource I can find
>> online and on the uBlox forums, but there is a general lack of public
>> information about the time and clock features of the u-Blox F9 engine.
>>
>>     Suffice it to say, there is a section in the integration manual where
>> they elude the 1PPS signal is set to the closest one of 1023 edges - which
>> seems to suggest a possible sawtooth phase noise creation.  Talking with a
>> person "clive1" on the uBlox forum it sounds like the internal GPS engine
>>>> MAY<< now running at 384MHz there sounds like a possibility to align a
>> 1PPS edge to a much finer resolution clock which is closer tied to the GPS
>> solution and thus less digital divider phase noise might be possible.
>>
>>     Does it sound like I'm way out in left field here?  Anyone have the
>> luxury of more insight into the construction of the uBlox F9 GPS engine?  I
>> don't mind spending a few grand on some factory new components to get a
>> decent 10MHz standard, but I'm less interested in doing so if I'm not going
>> to understand what's going on inside.
>>
>> Thanks in advance for responses,
>>
>> -Tim Strommen
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at lists.febo.com
>> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>