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

From: Eric S. Raymond
Subject: Re: [gpsd-dev] A detail in your ntpoffset script
Date: Wed, 23 Oct 2013 16:17:07 -0400
User-agent: Mutt/1.5.21 (2010-09-15)

Gary E. Miller <address@hidden>:
> Acually.  It is much simpler.  There are USB 1.1 1024 time slots.  That
> works about to a time slot every 1 mSec.  Each device is always polled
> in the same time slot.  The time slots are derived from the system
> clock.  So once the system clock is stable the sample instant is euqally
> stable.  Once it settles I get an observed stability of one part in
> about 1,000.

Aha. So *that's* why USB time latency is so freaking steady.  Good to
know.  Maybe should go in the HOWTO.
                <a href="";>Eric S. Raymond</a>

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