Thanks all for their comments on this topic.
Over the weekend I spent much time messing about with the NTP stuff and the NMEAGps application. NMEAGps does just as described and does make a nice IRIG-B signal through a PC's sound card. Unfortunately you cannot specifiy which of several soundcard interfaces you want it to use, it will use the one as set as the default which for my use does not work so well. Set up on a second PC set up as a NTP server and time code generator may just be answer. Some more thought is needed before I figure out how to make it do what I want or to dismiss it. There is also the possibility of adapting "tc" as suggested by Chris A. Cheers, Graham -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Chris Albertson Sent: December 3, 2010 18:03 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Time Code generator You computer can generate "time code" audio signals and if you are keeping the computer's clock sync'd with NTP then those generated time codes will be reasonably accurate. The time code generator is distributed with the NTP software along with other misc. tools. It's a free download if you don't have it. The code is I think the same as sent by WWV. It is some IRIG version. It hing the name of the time code generator is just "tc". There is a good chance you alreasy have this but if not it's in the NTP source distribution OK I just looked it up. The filename is .../util/tg.c and here is a quote from the file * This program can generate audio signals that simulate the WWV/H * broadcast timecode. Alternatively, it can generate the IRIG-B * timecode commonly used to synchronize laboratory equipment. later NTP can read back this time code and sync a clock to it. We do this "all the time" when recording rocket telemetry at work. It works pretty much exactly the way the OP wanted I thing this implementation in tg.c is good to about 1 millisecond -- ===== Chris Albertson Redondo Beach, California _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
