[time-nuts] PPS for NTP Server - How Close Is "Good Enough"?
hmurray at megapathdsl.net
Wed Jun 10 09:00:29 UTC 2015
eds_equipment at verizon.net said:
> OK, here is the actual question. Do you think it is OK to consider a pulse
> which arise 250 ns early to be close enough? And no, I am not forgetting
> about that 3 ns, there is about 3 ns of delay added by the output
If you want to earn your time-nut merit badge, you have to measure it.
The Ethernet on the Raspberry Pi is on the USB bus. That adds about a 1/2 ms
If you are using ntpd, there is a fudge factor that lets you correct for any
offset. (and another one that lets you use the other edge, but I think the
Pi doesn't capture it)
These are my opinions. I hate spam.
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