[time-nuts] Time Code generator

[Collins, Graham]

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: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] 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

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