On 2014-09-03, Harlan Stenn st...@ntp.org wrote:
Charles Elliott writes:
It is possible to distribute more accurate and stable time using a local GPS
device, either home built (e.g.,
If you are using an operating system like linux or bsd and the GPS puts
out
a PPS signal then yes. If
windows
On Wed, Sep 3, 2014 at 10:30 AM, William Unruh un...@invalid.ca wrote:
Without PPS, the GPS has an accuracy (delay and fluctuation)
in the tens of milliseconds range
Most of the time but, of course, not always. From my stable NMEA
source (also using PPS):
remote: oPPS(0)
offset: -0.002
: questions-bounces+elliott.ch=comcast@lists.ntp.org
[mailto:questions-bounces+elliott.ch=comcast@lists.ntp.org] On
Behalf Of jthul...@gmail.com
Sent: Sunday, June 15, 2014 11:30 PM
To: questions@lists.ntp.org
Subject: [ntp:questions] About use of PPS in NTP sync
Hello,
I'm
Charles Elliott writes:
It is possible to distribute more accurate and stable time using a local GPS
device, either home built (e.g.,
http://www.satsignal.eu/raspberry-pi/index.html) or purchased (e.g.,
http://www.meinberg-usa.com/products/network-time-server.htm), but the
original cost is
jthul...@gmail.com wrote:
Does it mean that if I set the minpoll and maxpoll values to 4
If you do that for external servers, they may consider that abuse.
For _your_ / _your_companies_ servers it can be anything you want.
For _your_ reference clocks whatever works best.
--
E-Mail Sent to
Hi,
the PPS signal comes from one GPS clock.
At the cold start the drift could be several seconds, so we plan to perform a
ntpdate before launching the ntp client.
The sync accuracy we want to achieve for this particular system is below 3ms
offset.
After the ntpdate we assume that the offset
jthul...@gmail.com writes:
Hi,
the PPS signal comes from one GPS clock.
At the cold start the drift could be several seconds, so we plan to
perform a ntpdate before launching the ntp client.
That sounds like the offset is possibly several seconds. I was asking
about drift (frequency
jthul...@gmail.com jthul...@gmail.com wrote:
Hello,
I'm looking for a way to speed up the ntp convergence of a system which would
be restarted after several days being off. Does the use of PPS improve this
convergence time ?
This is local configuration, with one LAN and one NTP server, with
jthul...@gmail.com jthul...@gmail.com wrote:
Hi,
the PPS signal comes from one GPS clock.
At the cold start the drift could be several seconds, so we plan to perform a
ntpdate before launching the ntp client.
The sync accuracy we want to achieve for this particular system is below 3ms
On 16/06/2014 09:29, jthul...@gmail.com wrote:
I've never used ntpdate, just the appropriate option to ntpd at startup.
Is it ignore_bigtimestep yes ?
Does it enable the realignment of a client with several seconds offset ?
It's the -g parameter, I believe:
I've never used ntpdate, just the appropriate option to ntpd at startup.
Is it ignore_bigtimestep yes ?
Does it enable the realignment of a client with several seconds offset ?
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PPS makes the final convergence a lot faster, because it is usually being
run at a high sample rate (once every 16 seconds).
Watch your 'minpoll' and 'maxpoll' values.
Does it mean that if I set the minpoll and maxpoll values to 4, I will have a
convergence time result almost as good as
On 16/06/14 07:08, jthul...@gmail.com wrote:
Hi,
the PPS signal comes from one GPS clock.
At the cold start the drift could be several seconds, so we plan to perform a
ntpdate before launching the ntp client.
The sync accuracy we want to achieve for this particular system is below 3ms
The objective here of a 3ms offset is pretty conservative so I am inclined to
prefer connecting the PPS clock to the NTP server if that is running all the
time, and the clinet(s) are not behind old tech routers/switches. There does
not appear to me to be much benefit from having the PPS
On 2014-06-16, jthul...@gmail.com jthul...@gmail.com wrote:
Hello,
I'm looking for a way to speed up the ntp convergence of a system which would
be restarted after several days being off. Does the use of PPS improve this
convergence time ?
This is local configuration, with one LAN and one
On -10.01.-28163 20:59, jthul...@gmail.com wrote:
I'm looking for a way to speed up the ntp convergence of a system
which would be restarted after several days being off.
Since you seem concerned about additional frequency offset while the
system warms up: Can you turn it on (and, say, let it
jthul...@gmail.com jthul...@gmail.com wrote:
PPS makes the final convergence a lot faster, because it is usually being
run at a high sample rate (once every 16 seconds).
Watch your 'minpoll' and 'maxpoll' values.
Does it mean that if I set the minpoll and maxpoll values to 4, I will have
Jochen Bern jochen.b...@linworks.de wrote:
On -10.01.-28163 20:59, jthul...@gmail.com wrote:
I'm looking for a way to speed up the ntp convergence of a system
which would be restarted after several days being off.
Since you seem concerned about additional frequency offset while the
system
Hello,
I'm looking for a way to speed up the ntp convergence of a system which would
be restarted after several days being off. Does the use of PPS improve this
convergence time ?
This is local configuration, with one LAN and one NTP server, with about 30 NTP
clients.
Thank you.
JT
jthul...@gmail.com writes:
Hello,
I'm looking for a way to speed up the ntp convergence of a system
which would be restarted after several days being off. Does the use of
PPS improve this convergence time ?
This is local configuration, with one LAN and one NTP server, with
about 30 NTP
On 16/06/2014 04:29, jthul...@gmail.com wrote:
Hello,
I'm looking for a way to speed up the ntp convergence of a system which would
be restarted after several days being off. Does the use of PPS improve this
convergence time ?
This is local configuration, with one LAN and one NTP server, with
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