On 06/25/19 10:52, David Taylor wrote:
On 25/06/2019 01:33, Chris wrote:
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Thanks for all the replies. I guess the next thing to do is to build
a working system, then evaluate to see how it can be improved. All
the kit is in the same rack and with dedicated hardware interfaces,
network latency shouldn't be a problem. This is effectively a real
time requirement, so any code running needs to be consistent in terms
of response time to minimise jitter on the timing. Need to get
a feel for acceptable delay and response times, so will look to see
what others have done in the past.
I like the idea of using a 1 pps signal from the gps for fine tuning.
Rough time and date via the network ntp and the 1pps to fine tune it.
That could maintain the stratum 1 timing quality, as the 1pps is
generally within 10's of nS of UTC, but need to look into how ntpd
would handle that and also how to introduce that into the system.
Already use an ex telco gps for a lab frequency standard, but of
course, frequency != time of day. A dedicated embedded solution might
be the best bet, but other options might include a cheap netgear
router to provide the isolation, as it would only be handling ntp
packets at low and consistent system and network load.
Nothing is ever as easy as it seems, as usual...
Chris
Chris, would one or more of these help?
http://www.leobodnar.com/shop/index.php?main_page=product_info&products_id=272
No OS to get in the way.
Thanks, neat looking box, but already have the gps ntp servers. The
question was how to maintain the stratum one accuracy while
going through a firewall device to the net. looks like all the
hard work has been done though. Open source comes to the rescue
yet again...
Chris
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