[ntp:questions] fudge time1 for gps-18x-LVC?

David J Taylor david-taylor at blueyonder.delete-this-bit.and-this-part.co.uk.invalid
Sun Feb 7 16:43:11 UTC 2010

"Dave Hart" <davehart at gmail.com> wrote in message 
news:af01aefe-318a-49b3-bec0-a451724ce1c1 at b1g2000prc.googlegroups.com...
> It used to be the case that drivers that implemented their own PPSAPI
> handling, including the NMEA driver (20), relied on code in the ATOM
> driver (22) to filter the PPS samples over a polling interval into a
> single offset.  Last April, Dr. Mills relocated that code to
> ntp_refclock.c in new common PPSAPI handling code used by several
> drivers, including the Spectracom/WWVB driver, NMEA driver, ATOM
> driver, and to some extent, the parse drivers.
> The driver which supports PPS independent of any other timecode/
> refclock is the ATOM driver, number 22.  The PPSAPI code in 4.2.6's
> ATOM and NMEA drivers is essentially the same, the difference is
> whether it's used independently or associated with a NMEA source.
> Used independently, there must be at least one other source marked
> prefer.
> Cheers,
> Dave Hart


Many thanks for this - you have a closer and much clearer view of the code 
than I do, and I'm sure your replies will help David Lord as well.  Much 

If I have understood what you say correctly, then I don't quite see what 
use is served by specifying the ATOM driver in addition to the current 
(4.2.6 or later) NMEA driver (with a PPS signal fed to the serial port). 
Or is my view being hampered by the existence of the kernel-mode serial 
driver for Windows?


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