Answers inline
> On Jan 19, 2021, at 16:27, Bob kb8tq wrote:
>
> Hi
>
> Assuming the goal is a normal ADEV or xDEV sort of calculation:
>
> If you replace the raw phase values with zero that can mess things up
>
> 0 seconds +20 ns
> 1 seconds +22 ns
> 2 seconds +23 ns
> 3 seconds +25 ns
> 4
Hello Gilles
There's a reasonable way of treating data with gaps in it:
https://iopscience.iop.org/article/10.1088/0026-1394/45/6/S19
Essentially, any averaging interval with missing data is dropped from
the ADEV summation.
This reduces the number of intervals averaged over and increases the
Hi
Assuming the goal is a normal ADEV or xDEV sort of calculation:
If you replace the raw phase values with zero that can mess things up
0 seconds +20 ns
1 seconds +22 ns
2 seconds +23 ns
3 seconds +25 ns
4 seconds +27ns
5 seconds +29 ns
If you “loose” one of those 20 to 30 ns values and
Or one can replace those values with zero. That eliminates them; averaging then
proceeds without those values altering the most probable correct average.
DaveD
> On Jan 19, 2021, at 08:49, Bob kb8tq wrote:
>
> Hi
>
> The normal approach to filling a gap is to put in a point that is the
Hi
The normal approach to filling a gap is to put in a point that is the average
of the two adjacent points. The assumption is that this is a “safe” value that
will not blow up the result. That’s probably ok if it is done rarely. The risk
is
that you are running a filter process (averaging is a
Hi,
Yes outliers removal creates gap in Stable32.
The « fill » function can fills gaps with interpolated values.
It does not change much the graphs, except in the low Tau area (see attached).
Do you know a discussion of impact of outliers removal ?
Gilles.
> Le 18 janv. 2021 à 22:06, Bob
Hi
As you throw away samples that are far off the mean, you reduce the sample
rate ( or at least create gaps in the record). Dealing with that could be
difficult.
Bob
> On Jan 18, 2021, at 1:33 PM, Gilles Clement wrote:
>
>> Hi
>>
>> Very cool !!!
>>
>> The red trace is obviously the one
> Hi
>
> Very cool !!!
>
> The red trace is obviously the one to focus on. Some sort of digital loop that
> only operates under the “known good” conditions would seem to make sense.
>
> Thanks for sharing
>
> Bob
Hi,
I tried something with the idea to consider night records fluctuations as
HP journal
On Saturday, January 16, 2021, 12:29:24 PM GMT+1, Gilles Clement
wrote:
Hi Paul,
> I guess I would ask what the goal of the effort might be.
> It seems like a good answer. One thing I was amazed buy was that back in
> the 1960s HP wrote some papers on using WWVB. What they
Hi Paul,
> I guess I would ask what the goal of the effort might be.
> It seems like a good answer. One thing I was amazed buy was that back in
> the 1960s HP wrote some papers on using WWVB. What they did was check the
> offset at distance everyday about the same time. This offered quite a bit
>
There is an earlier NIST publication on the problems here -
https://nvlpubs.nist.gov/nistpubs/jres/64D/jresv64Dn3p239_A1b.pdf
John
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It's a custom LF receiver I put together, a direct conversion downconverter
to 1kHz. Then bandpass sampling to an I/Q data steam, at 12 bit resolution
sent using RS422 o a PC. All frequency conversion and sampling is locked to
a master 10MHz clock. The interface also includes time stamping from a
Sorry, forgot to include the cite:
LATHAM, D. Diurnal Frequency Variation and Refraction Index. Nature
Physical Science 234, 157–158 (1971).
https://doi.org/10.1038/physci234157a0
Don
On 2021-01-15 15:13, Andy Talbot wrote:
I did a plot of the phase of the UK 198kHz longwave transmission to
What was the program that you used for the plot please?
Regards
Paul
WB8TSL
On Fri, Jan 15, 2021 at 5:54 PM Andy Talbot wrote:
> I did a plot of the phase of the UK 198kHz longwave transmission to me, a
> path of about 150km, compared against an HP5061A Caesium standard
> N
>
> early 24 hours
Longwave phase is dependent on the weather between your receiver and the
transmitter...
On 2021-01-15 15:13, Andy Talbot wrote:
I did a plot of the phase of the UK 198kHz longwave transmission to me,
a
path of about 150km, compared against an HP5061A Caesium standard
N
early 24 hours
Hi JF,
DCF77 is more distant, less powerful and probably more polluted (77kHz).
Anyhow I would probably not be able to measure better than 10e-11 with current
setup (need a better reference)
Indeed a good and stable phase lock was not easy to reach.
I experienced the day and night huge
Hi
Very cool !!!
The red trace is obviously the one to focus on. Some sort of digital loop that
only operates under the “known good” conditions would seem to make sense.
Thanks for sharing
Bob
> On Jan 15, 2021, at 9:51 AM, Gilles Clement wrote:
>
> Hi,
>
> This is to share current
I guess I would ask what the goal of the effort might be.
It seems like a good answer. One thing I was amazed buy was that back in
the 1960s HP wrote some papers on using WWVB. What they did was check the
offset at distance everyday about the same time. This offered quite a bit
more accuracy and
Hi,
800Kw according to the press release of ANFR. I doubt it is the best choice :
DCF77 is more precise (active hydrogen maser) but a little bit more distant...
But the phase lock of a quartz on a VLF signal is not as easy. There is a
considerable phase shift in the evening and in the morning
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