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Re: [questions] GPS+PPS vs NTP server, why a huge offset ?



On 19/06/2022 07:30, Daniel O'Connor wrote:
I think for standard PC timing in a network it is more than adequate.
Using PPS over USB does give you an improvement over just serial traffic so why not use it since it's free.

Sure, but I would think something with an input capture timer will produce a better result again. It is just unfortunate the RPi can't do it.

If PPS over USB is all you have, of course use it. But if you have a local stratum-1 server it's likely to produce much better results, just using a LAN connection.

Probably on the RPi using an input capture timer wouldn't produce much better results than simply using the GPIO pins and the the built-in kernel PPS support and reference NTP. I tend to think of the RPi alone as "tens of microseconds or better", and capture timer (PTP) as sub-microsecond level. Both are quite adequate for "standard PC timing".

Cheers,
David
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