I'm using a soekris net4501 that I hacked according to http://www.febo.com/time-freq/ntp/soekris/ I have hacked a Motorola Oncore M12+T receiver inside the case on a piece of veroboard. It's really ugly, using a bunch of discretes for RS232 translation and such. A BNC on the front privides PPS for use with other external hardware. Recenlty I felt the need to add hardware sawtooth correction. I want to use the Dallas DS1023 chip to do this. I designed a little board as a 'carrier' for the motorola, a little micro, the delay line for sawtooth correction and rs232 for the soekris (but could, of course, also be used to connect to any other device that has RS232). I was wondering if there was any interest from other people for a little board like this. I don't have the parts yet, but the DS1023 is pretty much the most exotic part on the board. I have attached some pictures of the design. Regards, Tom

Hi Tom, I would certainly be interested. I have 4 receivers that I would like to add that feature to. I was thinking of also trying the technique with other receivers, such as Trimble Jupiter/SMT or newer Ublox which provide quantization data so I was thinking of a more generic serial/PPS pass through which could handle all those protocols quantization messages. > Le 3 déc. 2014 à 04:56, Tom Wimmenhove <tom.wimmenhove@gmail.com> a écrit : > > I'm using a soekris net4501 that I hacked according to > http://www.febo.com/time-freq/ntp/soekris/ > I have hacked a Motorola Oncore M12+T receiver inside the case on a piece > of veroboard. It's really ugly, using a bunch of discretes for RS232 > translation and such. > A BNC on the front privides PPS for use with other external hardware. > Recenlty I felt the need to add hardware sawtooth correction. I want to use > the Dallas DS1023 chip to do this. I designed a little board as a 'carrier' > for the motorola, a little micro, the delay line for sawtooth correction > and rs232 for the soekris (but could, of course, also be used to connect to > any other device that has RS232). > > I was wondering if there was any interest from other people for a little > board like this. I don't have the parts yet, but the DS1023 is pretty much > the most exotic part on the board. > > I have attached some pictures of the design. > > Regards, > Tom > <gps_bottom.png><gps_top.png>_______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.

-------- In message <DECE7BA6-65E7-4C1E-A424-7E258A020E84@sfr.fr>, Mike Cook writes: >> I'm using a soekris net4501 that I hacked according to >> http://www.febo.com/time-freq/ntp/soekris/ >> Recenlty I felt the need to add hardware sawtooth correction. For the net4501 that is probably a bad idea. When you do the sawtooth correction in software, the hw-component acts as a jitter to smooth out the net4501's ~120nsec timestamping window. Without this jitter, you will have the timestamps sit in the same window for long periods of a time and then suddenly switch to to the neighboring window rather rapidly. With the jitter the switch gets "smeared" out over a longer period of time, which is a more sensible input to a PLL. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.

Poul, This is a good point and I hadn't thought of that. I'll make sure the pin header going over to the soekris board will still receive the 'dirty' PPS signal, and route the corrected signal only to the SMA connector on the board. On Wed, Dec 3, 2014 at 1:49 AM, Poul-Henning Kamp <phk@phk.freebsd.dk> wrote: > -------- > In message <DECE7BA6-65E7-4C1E-A424-7E258A020E84@sfr.fr>, Mike Cook > writes: > > >> I'm using a soekris net4501 that I hacked according to > >> http://www.febo.com/time-freq/ntp/soekris/ > > >> Recenlty I felt the need to add hardware sawtooth correction. > > For the net4501 that is probably a bad idea. > > When you do the sawtooth correction in software, the hw-component > acts as a jitter to smooth out the net4501's ~120nsec timestamping > window. > > Without this jitter, you will have the timestamps sit in the same > window for long periods of a time and then suddenly switch to to > the neighboring window rather rapidly. > > With the jitter the switch gets "smeared" out over a longer > period of time, which is a more sensible input to a PLL. > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > phk@FreeBSD.ORG | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >