On Thu, Jun 14, 2012 at 3:59 AM, <shali...@gmail.com> wrote: > Acrually the PPS output has very low impedance, so you can probably load it > with 5 instruments, each with 50 termination.
My problem with PPS distribution was the fast raise time got "smeared" by the long cable. Lots of guesses about why. Could be reflections off the end, capacitance in the cable. The problem is that I want WAY under 1 microsecond level performance out of a PPS signal. The trouble is that the PPS is a single ended signal and the leading edge is defined by some voltage threshold. So it is sensitive to noise. Two solutions I found (1) differential transmitters and receivers at each end, like RS-422 type work, or (2) simply move the thunderbolt physicaly close and use an 18 inch cable. Take my word for it, the T-Bolt is not able to drive a 100 foot long twisted pair cable > > Not so for the 10MHz though > > Didier KO4BB > > Sent from my BlackBerry Wireless thingy while I do other things... > > -----Original Message----- > From: "David C. Partridge" <david.partri...@perdrix.co.uk> > Sender: time-nuts-boun...@febo.com > Date: Thu, 14 Jun 2012 01:59:42 > To: 'Chris Wilson'<ch...@chriswilson.tv>; 'Discussion of precise time and > frequency measurement'<time-nuts@febo.com> > Reply-To: Discussion of precise time and frequency measurement > <time-nuts@febo.com> > Subject: Re: [time-nuts] Another ThunderBolt cabling question > > No you can't load the 10MHz (or the PPS) with five instruments in parallel. > You need a distribution amplifier. > > Dave > -----Original Message----- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Chris Wilson > Sent: 13 June 2012 22:33 > To: Discussion of precise time and frequency measurement > Subject: [time-nuts] Another ThunderBolt cabling question > > > > 13/06/2012 22:27 > > About to do the permanent installation, if I bring two leads from the 10 MHz > and 1 PPS BNC sockets on the TB to a panel in my shck can i have say 5 BNC > sockets on the panel wired in parallel, with the lead from the 10 MHz socket > on the TB feeding them all? And a single socket for the 1 PPS? Any need to > screen the back of the socket panel, or enclose it in a metal box? Cheers. > > Oh, I have been running lady Heather for a while tonight, here's a screen > capture, does it look OK, ther's suddenly just two traces appeared? Thanks. > http://www.chriswilson.tv/heather.png > > -- > Best Regards, > Chris Wilson. > mailto: ch...@chriswilson.tv > > > _______________________________________________ > 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. > > > _______________________________________________ > 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. > _______________________________________________ > 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. -- Chris Albertson Redondo Beach, California _______________________________________________ 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.
