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Re: [gpsd-dev] A detail in your ntpoffset script

From: Beat Bolli
Subject: Re: [gpsd-dev] A detail in your ntpoffset script
Date: Wed, 23 Oct 2013 21:15:03 +0200
User-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:24.0) Gecko/20100101 Thunderbird/24.0.1

On 23.10.13 01:22, Eric S. Raymond wrote:
> Beat Bolli <address@hidden>:
>> This is correct, but I was assuming that the PPS doesn't have to be
>> fudged, because it is directly connected to the kernel PPS via an
>> interrupt. I have a fudge offset only on the GPS unit, and none on the
>> PPS. This seems to make sense to me, because only the NMEA stuff is
>> delayed by the RS232 transmission.
> Ahh. OK, I think I get it. So step 5 should read like this, then?
> 5. Adjust the "time1" value for unit 0 of your ntp.conf (the non-PPS
>    channel) by subtracting the average offset from step 4.

That's right.

Of course, if one wanted to fudge the PPS too, a similar procedure would
have to be done for unit 1 (one more requirement for ntptune!)

mail: echo '<address@hidden>' | tr -d '[A-S]'
pgp: 0x506A903A; 49D5 794A EA77 F907 764F  D89E 304B 93CF 506A 903A
icbm: 47.0452 N, 7.2715 E

"It takes love over gold, and mind over matter" -- Dire Straits

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