> -----Original Message----- > From: questions- > [email protected] > [mailto:questions- > [email protected]] On > Behalf Of A C > Sent: Tuesday, August 23, 2011 8:25 PM > To: [email protected] > Subject: Re: [ntp:questions] Fwd: Re: NetBSD GPS/PPS using > 4.2.6p3 > > On 8/23/2011 15:27, unruh wrote: > > On 2011-08-23, Uwe Klein<[email protected]> wrote: > >> unruh wrote: > >>> But from his test, his system is labelling both edges. > >>> > >> so he has bounces on the line? > >> > >> either that or rise/falltime is so low and noise so high > >> that receiver hysteris is not sufficient to supress multiple > >> HL/LH changes? > > > > No, his test shows that the line changes and then 100ms later > it changes > > back and 900ms later it changes again (ie once per second it > rises and > > falls.) Ie, it is behaving exactly as it should if it were > detecting a > > pulse 100ms long.It is detecting both the rising and falling > edge. > > I just checked and the pulse is almost exactly 100 ms low going > and 900 > ms high (within about 1 ms) so it's 90% duty cycle high most of > the time > with a swing low. The signal itself is clean down to microvolt > levels. > The total voltage swing is about 12 volts (which would stand > to reason > since I'm feeding the TTL level PPS output of the GPS board > through one > channel of a MAX232 level shifter). > > Therefore the machine is receiving a nice, clean PPS signal on > DCD (DCD > pin was also verified yet again and is correct by hardware > specifications). [Mischanko, Edward T] Seems like your PPS pulse is inverted? You may want to add Flag2 1 to your fudge line.
server 127.127.22.1 fudge 127.127.22.1 flag2 0 flag3 1 refid PPS > _______________________________________________ > questions mailing list > [email protected] > http://lists.ntp.org/listinfo/questions _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
