[time-nuts] Raspberry Pi NTP server

[Matthias Welwarsky]

On Samstag, 4. Juli 2020 16:49:11 CEST David J Taylor via time-nuts wrote:

> Matthias, my feeling is that if you want a precision source, neither BB not
> the RPi is a good solution.  Maybe with all the tweak you mentioned the BB
> approaches precision (for some values of precision).  I see the RPi as
> something which can provide far better NTP than simply using an Internet
> source, something which will be adequate for the majority of users (for some
> types of user!).

If your wall clock runs locked to GPS time, which it is by definition if you 
drive its counter directly from a GPSDO, then it cannot drift away from GPS 
time. If you timestamp the 1PPS pulse from the same GPSDO using the same 
counter in capture mode, the NTP server will have easy game once the initial 
time stepping is done. The system time will always be locked to GPS time, with 
a 100ns uncertainty given by the counter granularity when clocked with 10 MHz. 
This is the baseline of what can be achieved with such setup. Everything else 
is a question of your time distribution system.

As far as "for some types of users" is concerned - this list is called "time-
nuts" for a reason, isn't it?

:-)

Best regards,
Matthias