[ntp:questions] How to debug PPS?

David J Taylor david-taylor at blueyonder.co.uk.invalid
Fri Apr 23 05:50:50 UTC 2010

"Chaofu Chen" <> wrote in message 
news:90005.53446.qm at web45014.mail.sp1.yahoo.com...
> Hi all. I want to build a NTP server but PPS doen't work for the time 
> being. Status bits from "ntptime" and "ntpdc -c kern" include PLL and 
> NANO, sometimes PPSTIME and PPSFREQ, but PPSSIGNAL never appears.
> Any suggestions or help will be appreciated.

What does the error log say?  Sorry, but I don't know where to find it in 
FreeBSD (I mostly use Windows and the Event Viewer).

>From my own FreeBSD system I get:

ntpdc -c kern pixie

pll offset:           0.003816 s
pll frequency:        24.359 ppm
maximum error:        0.007024 s
estimated error:      2e-006 s
status:               2107
pll time constant:    4
precision:            1e-006 s
frequency tolerance:  496 ppm
pps frequency:        24.359 ppm
pps stability:        0.026 ppm
pps jitter:           0.002609 s
calibration interval: 256 s
calibration cycles:   4933
jitter exceeded:      1181
stability exceeded:   0
calibration errors:   2

and the timekeeping is within about 10 microseconds (mainly temperature 
change limited):



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