[time-nuts] Frequency Ensemble

[Michael Wouters]

Oops, units for TDEV are seconds, not nanoseconds!

On Wed, 20 Mar 2019 at 7:41 pm, Michael Wouters <michaeljwouters at gmail.com>
wrote:

> Hello Dan,
>
>
> As promised here is a comparison of the ZED-F9P and NEO-M8T
> sawtooth-corrected PPS. The PPS is measured against a 5071 with standard
> tube. Three days of data were used. The 5071 was measured against another
> 5071 and I divided the TDEV by sqrt(2). The 5071 data at shorter than 300s
> is limited by the counter resolution so I didn't show it. The ZED-F9P is
> significantly better than the M8T between 10 and 1000 s but much the same
> past 10000s.
>
> Cheers
> Michael
>
> On Tue, 19 Mar 2019 at 8:02 am, Dan Kemppainen <dan at irtelemetrics.com>
> wrote:
>
>> Bob,
>>
>> I recalled the plot you posted a few days ago. Nice plot on the F9P,
>> BTW. Thanks for posting that.
>>
>> I don't supposed you happened to be recording a similar plot with a L1
>> only Ublox part at the same time by chance, did you? I think it would be
>> interesting to compare a 6T or M8 part to the F9P. (I lack a standard
>> good enough to compare them to...)
>>
>> Thanks!
>> Dan
>>
>>
>>
>>
>> On 3/18/2019 1:00 PM, time-nuts-request at lists.febo.com wrote:
>> > Message: 2
>> > Date: Mon, 18 Mar 2019 12:26:55 -0400
>> > From: Bob kb8tq<kb8tq at n1k.org>
>> > To: Discussion of precise time and frequency measurement
>> >       <time-nuts at lists.febo.com>
>> > Subject: Re: [time-nuts] Frequency Ensemble
>> > Message-ID:<88460EA2-6034-48D1-A77A-FED1F824D843 at n1k.org>
>> > Content-Type: text/plain;     charset=utf-8
>> >
>> > Hi
>> >
>> > There are a variety of GPS devices that put out a PPS. uBlox makes
>> some, there
>> > are a number of other companies that do so. The PPS comes out modulo
>> the local
>> > timebase. On a precision part, there is a ?sawtooth correction? message
>> that also
>> > comes out to further quantify the best guess time of that pulse.
>> >
>> > Noise wise, even with correction you are lucky to get a one second ADEV
>> in the
>> > 1 to 2 ppb range with a typical L1 receiver. With a L1 / L2 device like
>> the F9P,
>> > you might do a bit better than that.
>> >
>> > The ADEV of your other sources at short tau will be much better than
>> the GPS PPS
>> > noise. As you average out over long periods, the GPS will win the race.
>> >
>> > Bob
>>
>> _______________________________________________
>> 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.
>>
>