On 2007-03-31, Spoon <[EMAIL PROTECTED]> wrote: > Steve Kostecke wrote: > >> Provide your ntpd with a stable PPS source and use the Undisciplined >> Local Clock. > > I am running Linux 2.6.20.3-rt8 > > I don't think vanilla 2.6 supports PPS sources at the moment?
You could bring up a system running a Linux kernel version with PPSkit support. Or you could bring up a FreeBSD system. > In my situation, I don't care what time it is, but my clock needs > to tick at the correct rate. The least expensive means of getting your clock to tick at the correct rate is to synchronize it to the ubiquitous time-base known as UTC. > I think I can't use GPS because the computer is located in a server > room underground. Can you run an antenna cable down to the bunker? That would allow you so place an antenna top-side and the GPS receiver underground: http://www.meinberg.de/english/products/gps170pci.htm http://www.microsystemes.com/PDF%20FICHES%20PRODUITS/fp0156.pdf http://www.spectracomcorp.com/Home/Products/BuslevelTimingBoards/TSATPCIGPSTimingBoard/tabid/378/Default.aspx If you can receive CDMA cellphone signals in the bunker you could use a product such as the Endrun Technologies PraecisCT: http://www.endruntechnologies.com/network-time-source.htm > Are there other PPS sources? I've read about rubidium and cesium clock > sources. How expensive are they? Here's one rubidium oscillator (you'd have to package it into a complete solution): Sanford Research PRS10 $1495 US / $1695 international Here are some links for complete solutions (you have to request prices): http://www.bvsystems.com/Products/Lab/Rhino/rhino.htm http://www.labx.com/v2/spiderdealer2/vistasearchdetails.cfm?LVid=3345327 You should be able to find more using your favorite search engine. -- Steve Kostecke <[EMAIL PROTECTED]> NTP Public Services Project - http://ntp.isc.org/ _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
