> Tom
>
> A TIC with 0.5ns jitter at 1 second isn't actually too much in the way
> of overkill when the PPS signal has 2ns of jitter.
Bruce,
Can you clarify about the jitter, though. The TIC jitter
that was quoted (500 ps) is the single-shot resolution
for the 53131A. The "2 ns" M12+ jitter is
Said,
The CNS-II outputs a raw hardware sawtooth corrected
1PPS and this is by design; it's not a mistake. There is
or may be a GPSDO version of the CNS-II clock but I
don't need it. What I (and some of the VLBI sites) use
the CNS for is to monitor the long-term performance of
masers and cesium cl
On Fri, December 15, 2006 0:55, Dr Bruce Griffiths said:
>
> Björn
>
> You will need a dual frequency receiver to more accurately correct for the
> ionospheric delay.
Sure, that is an improvement. But how large is really the time rate of
change of the ionosphere? (Depends on the solar activity nat
(I'm not sure you will be able to read this article for free.)
The most accurate clock of all time:
http://www.newscientist.com/article.ns?id=dn7397
Hidetoshi Katori and his colleagues at the University of Tokyo have built a
clock based on strontium atoms trapped in an optical lattic
In a message dated 12/14/2006 16:46:10 Pacific Standard /tvb writes:
The beauty of a GPSDO is that you're only changing
the DAC every few minutes so there's plenty of time
to look carefully at the quality of your 1 Hz samples
before you commit the DAC update.
It would be a more difficu
Hi Randy,
I will do a longer-term test with +-50ns setting. That should be interesting
:)
bye,
Said
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Does anyone have information on the PTS 250 Synthesizer?
I bought one on eBay. Seems to work pretty well, except the OCXO is not
great. I have a hard time even setting it below about 5x10^-9, but
output seems accurate and functional if I use external 10 MHz.
Do cal and service manuals exist for t
From: [EMAIL PROTECTED]
Subject: Re: [time-nuts] LPRO-101 with Brooks Shera's GPS locking circuit
Date: Fri, 15 Dec 2006 00:21:25 +0100 (CET)
Message-ID: <[EMAIL PROTECTED]>
> On Thu, December 14, 2006 23:07, Dr Bruce Griffiths said:
>
> > Thus devising inexpensive phase detectors/TICs with subna
From: Dr Bruce Griffiths <[EMAIL PROTECTED]>
Subject: Re: [time-nuts] LPRO-101 with Brooks Shera's GPS locking circuit
Date: Fri, 15 Dec 2006 12:55:19 +1300
Message-ID: <[EMAIL PROTECTED]>
> Björn
Bruce,
> You will need a dual frequency receiver to more accurately correct for the
> ionospheric
Brian,
I would not expect 250ns to cause any problems. The data I was talking
about yesterday was pretty old and S/A WAS on at that time which made it
much harder to keep the 1PPS accurate. I would hope that the firmware in
the receivers has been improved too.
Randy
___
I use TAC32 Plus with my Motorola M12+ receiver. You can set TRAIM
between 250 to 1000 nanoseconds. Default is 500 nS. I have had mine
set at 250 nS for years and have not noticed any problems - but, that is
a somewhat wide window.
Brian N4FMN
Randy Warner wrote:
> Said,
>
> Based on what
Said,
Based on what I have read from the Motorola side of things setting the
limits down that low will be problematic due to the constant threat of
spurious alarms. My concern would be that the "good" 1PPS time
accuracies might suffer if the receiver is constantly cycling. If the
software filters
In a message dated 12/14/2006 12:00:36 Pacific Standard Time,
[EMAIL PROTECTED] writes:
> Hello Said,
>
> from my own experience in detecting and removal of outliers i can asure
> you that it is a challenging and ambitious task in statistical math. I
> fear you expect too much from a receiv
[EMAIL PROTECTED] wrote:
> On Thu, December 14, 2006 23:07, Dr Bruce Griffiths said:
>
>
>> Thus devising inexpensive phase detectors/TICs with subnanosecond
>> performance allows one to take advantage of improvements in GPS timing
>> receiver performance when they occur.
>>
>> The possibility o
[EMAIL PROTECTED] wrote:
> On Thu, December 14, 2006 23:07, Dr Bruce Griffiths said:
>
>
>> Thus devising inexpensive phase detectors/TICs with subnanosecond
>> performance allows one to take advantage of improvements in GPS timing
>> receiver performance when they occur.
>>
>> The possibility o
By unplugging the wrong cable on leaving my lab, I found out that my
Jupiter (nav) receiver drifted 180ms in 36h. A Meinberg GPS167, with a
standard OCXO drifted 1.8ms in the same time.
--
Björn
On Fri, December 15, 2006 0:18, Randy Warner said:
> Hal,
>
> I can't speak for all receivers, but
Does anyone out there have any service information on the FTS, (Datum), now
(Symetricomm) 4040A. I need the info on the newer style with the microprocessor
controller board. Around serial number 02200 I believe.
Thanks, Chuck Norton
___
time-nuts mail
On Thu, December 14, 2006 23:07, Dr Bruce Griffiths said:
> Thus devising inexpensive phase detectors/TICs with subnanosecond
> performance allows one to take advantage of improvements in GPS timing
> receiver performance when they occur.
>
> The possibility of utilising GPS carrier phase tracking
Hal,
I can't speak for all receivers, but the Motorola's decay gracefully for
about an hour. There will be a significant error (us level would be my
guess). I'll have to try one. Again, if you are a ns chaser this will
obviously be acceptable, but we have several customers that let the
receiver ru
> The beauty of a GPSDO is that you're only changing the DAC every few
> minutes so there's plenty of time to look carefully at the quality of
> your 1 Hz samples before you commit the DAC update.
I think this discussion started with somebody asking about the last few PPS
signals before the sign
Tom Van Baak wrote:
>> But is it really an improvement that you get out of it? The answer is
>> NO! He, why not? The answer is: Because you have to PAY the increase in
>> precision with the increase in observation time. For every increase of
>> 10 in precision you need to increase the observation t
> Hello Said,
>
> from my own experience in detecting and removal of outliers i can asure
> you that it is a challenging and ambitious task in statistical math. I
> fear you expect too much from a receiver's TRAIM firmware to compute the
> necessary statistic math on a pulse to pulse base. Neverthe
> But is it really an improvement that you get out of it? The answer is
> NO! He, why not? The answer is: Because you have to PAY the increase in
> precision with the increase in observation time. For every increase of
> 10 in precision you need to increase the observation time by 10!
Ulrich,
Th
> Does anyone know of any documents on how to deploy network time
> synchronization in a corporate environment?
> I don't need anything like Mill's book. Basically looking for
> something like a big white paper or a 20-30 page guide.
I don't know where to find something like that. I think Sun
Björn,
thank you for the link! Looks very interesting!
Regards
Ulrich Bangert, DF6JB
> -Ursprüngliche Nachricht-
> Von: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] Im Auftrag von [EMAIL PROTECTED]
> Gesendet: Donnerstag, 14. Dezember 2006 13:30
> An: Discussion of precise time and fre
I would think Symmetricom would have a lot of whitepapers on their site,
probably a good start.
Jason
> Need documentation on deploying a corporate time sync infrastructure
>
> Hello,
>
> Does anyone know of any documents on how to deploy network time
> synchronization in a corporate environme
Hi folks,
> On the subject of Brooks Shera's design, the one thing that
> troubles me is the use of a 24 MHz oscillator to count the
> width of the 1PPS signal. This yields a precision of 4.16e-8,
> but does it really?
> This oscillator is uncontrolled and any drift would exist
> as noise tha
I'm not sure if this timing is right for the coronal ejection to hit
earth, but I see from my NTP plots* that my WWVB receiver apparently
lost lock at about 0200 UTC last night. It looks like it recovered
within a half hour or so (I'll need to look at the logs in more detail
to figure out the
Need documentation on deploying a corporate time sync infrastructure
Hello,
Does anyone know of any documents on how to deploy network time
synchronization in a corporate environment?
I don't need anything like Mill's book. Basically looking for something
like a big white paper or a 20-30
Rob, Magnus thanks for helping me (on&off-list).
For the record. This display, at least this variant, was custom made and
listens only to a non-standard countdown timecode.
I belive there must have been "normal" IRIG-timecode-display versions of
this product as well. If someone have one and are w
I got a reply from FEI, and here is what he said about those RFG-RB units...
They use a special FE-5680A. (Don't ask me what is special about them, he
did not say.)
The physics package is designed to last 20 years.
He sent me a PDF that was 820k, the one linked below appears to have the
same inf
Yesterday, a coronal mass ejection from the sun was aimed
right at the Earth. There are lots of HF propagation
effects. Geosynch satellites could experience failures.
The major storm will end on the 16th.
Anybody notice anything in the time domain?
Bill Hawkins
_
Hi Dean,
Yep, I kind of put 2 & 2 together from an earlier post (I'm working my way
through all my emails this morning) and found the tg.c file in the ntp
distribution. Have not compiled it yet (about 1/2 way through all my
messages).
I would be interested in your modified tg.c, please by all mea
Tom,
This sounds really cool, be sure to let us know when you want to collect the
units, I would be willing to let you borrow whatever you want.
Don't suppose there's an exchange program where you loan out a Cesium or
Hydrogen Maser? lol j/k
Jason
> Early next year I plan to perform a head-to-h
Bruce,
It's cool, I understand what you were trying to say. Yes, I have seen many
"free" little programs out there (albeit 99% were probably for Windows, and
of those probably most were screen savers that people like to download
because they think they were 'cute') that were extremely poorly coded
Björn,
I have that page bookmarked, but I guess I must of missed that section! I
grabbed that code and will check it out, I also noticed he mentioned the
WWV/IRIG code in the utils folder in the NTP distribution. I checked out my
archive and sure enough the file tg.c is exactly what I'm looking fo
Hi Bruce,
Yes, I saw that program (and a couple other Windows apps), however I'm
really looking for something that will run on Linux/FreeBSD. Sorry if I'm
not a Windows fan.
I mentioned free because I am an open-source kind of guy, I do not think
that makes a product sub-standard. Also converting
Good day,
*** REPLY SEPARATOR ***
On 14-Dec-06 at 13:16 [EMAIL PROTECTED] wrote:
>Hi,
>
>Have not used this myself but it could be a starting point for what the OP
>wanted... free, working on unices etc.
>
> http://www.wraith.sf.ca.us/ntp/index.html#test-tones
>
>Bruce, be car
From: Scott Lacy <[EMAIL PROTECTED]>
Subject: [time-nuts] Poor Man's IRIG-B Generator?
Date: Thu, 14 Dec 2006 07:43:06 -0700
Message-ID: <[EMAIL PROTECTED]>
> Jason,
>
> The source tg.c is a sound card output IRIG-B (or WWV) generator.
>
> Find it here:
> http://debian.osuosl.org/debian/pool/ma
Jason,
The source tg.c is a sound card output IRIG-B (or WWV) generator.
Find it here:
http://debian.osuosl.org/debian/pool/main/n/ntp/ntp_4.2.0a+stable.orig.tar.gz
Let me know if you have trouble building it - I did get it to compile here.
-Scott
Tom Van Baak wrote:
>> On the subject of Brooks Shera's design, the one thing that troubles me is
>>
> the
>
>> use of a 24 MHz oscillator to count the width of the 1PPS signal.
>> This yields a precision of 4.16e-8, but does it really?
>>
>
> No, with averaging it's much better than t
Hi there,
The "standard" source package for the Network Time Protocol package,
found either at http://www.ntp.org or through download with/for a LINUX
distribution, has a tool in the "utils" directory called "tg", which
stands for "tone generator". It can generate simple modulated IRIG-B
and WWV(
Jack Hudler wrote:
> Bruce,
>
> Can you describe further your idea about phase detection using an ADC.
>
> Who produces the sinewave from the filtered counter?
>
> (Thinking out loud) Using a 10MHz oscillator as an example:
> Is this dividing the clock down to (say) 1 MHz and using a square->sine
Ulrich,
+-3 sigma is 99% on a gaussian distribution.
If you want to look at other algorithms on this topic, here is one:
http://www.control.isy.liu.se/books/adfilt/
br,
Björn
On Thu, December 14, 2006 12:55, Ulrich Bangert said:
> Hello Said,
>
> from my own experience in detecting and re
Hi,
Have not used this myself but it could be a starting point for what the OP
wanted... free, working on unices etc.
http://www.wraith.sf.ca.us/ntp/index.html#test-tones
Bruce, be careful when you equate "free" and substandard... In what way is
Dave Mills' reference implementation of NTP sub
Hello Said,
from my own experience in detecting and removal of outliers i can asure
you that it is a challenging and ambitious task in statistical math. I
fear you expect too much from a receiver's TRAIM firmware to compute the
necessary statistic math on a pulse to pulse base. Nevertheless you ca
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