[time-nuts] PPS for NTP Server - How Close Is "Good Enough"?

Hal Murray hmurray at megapathdsl.net
Sat Jun 13 06:02:38 UTC 2015

eds_equipment at verizon.net said:
> Is it possible to modify the kernel so the USB is polled more often, and
> would that significantly reduce the jitter? 

Modifying the kernel may not be enough if the timing parameters are in the 
microcode for the USB device.

Whether any improvement is significant probably depends upon your goals.  
It's unlikely to become a great NTP server.

If I wanted a good low power NTP server, I'd probably start with a BeagleBone 
Black.  I haven't seen a low cost no-assembly-required GPS board for the BBB  
(There is at least one GPS board for the BBB, but it includes a cell phone 
modem which doubles the cost.)  I'd probably try the GPS breakout board from 
SparkFun.  It should take 5 wires: power, ground, trans, recv, and PPS.  (and 
then the appropriate software hacking)

These are my opinions.  I hate spam.

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