clockworks

A few years ago a colleague did some dumpster diving and found a bunch of Gorgy Timing obsolete clocks using broadcast timecode signals to sync.

Without a dedicated network, this clock can't be synced.

Thanks to an obscure and forgotten NTP experimental binary able to generate WWV or IRIG signals, we can recreate a proper signalisation audio signal to sync the clock using the audio output port of a computer running linux.

Requirements

Hardware:

A trashed clock made for broadcast timecodes (can't help you find one)
A computer (laptop/embedded/Raspberry Pi...) with an open source distribution
An inline extension cord (preferably with a switch) to power the clock
An audio cable you will need to cut (TRS or TS, just two cables are needed)
4x connecting dominos if you don't want to do (bad) soldering.

Software:

docker and docker-buildx
make
¯\_(ツ)_/¯

Build (hardware)

Well, ...

You just need to power the clock with a regular 230V cable (or your local specification).

Same goes for the audio cable, I used a broken Beyerdynamic DT-770 3.5mm TRS jack for this.

Build (tg2)

$ make all

Run

If you're using pipewire or a recent distribution you may need to enable snd_pcm_oss kernel module to expose the audio device in /dev/audio

Make sure your default audio output is the right one!

$ sudo modprobe snd_pcm_oss
$ ./tg2

$ ./tg2 -h
Time Code Generation - IRIG-B or WWV, v0.23, 2007-02-12 dmw

RCS Info:
  $Header: /home/dmw/src/IRIG_generation/ntp-4.2.2p3/util/RCS/tg.c,v 1.28 2007/02/12 23:57:45 dmw Exp $

Usage: ./tg2 [option]*

Options: -a device_name                 Output audio device name (default /dev/audio)
         -b yymmddhhmm                  Remove leap second at end of minute specified
         -c seconds_to_send             Number of seconds to send (default 0 = forever)
         -d                             Start with IEEE 1344 DST active
         -f format_type                 i = Modulated IRIG-B 1998 (no year coded)
                                        2 = Modulated IRIG-B 2002 (year coded)
                                        3 = Modulated IRIG-B w/IEEE 1344 (year & control funcs) (default)
                                        4 = Unmodulated IRIG-B w/IEEE 1344 (year & control funcs)
                                        5 = Inverted unmodulated IRIG-B w/IEEE 1344 (year & control funcs)
                                        w = WWV(H)
         -g yymmddhhmm                  Switch into/out of DST at beginning of minute specified
         -i yymmddhhmm                  Insert leap second at end of minute specified
         -j                             Disable time rate correction against system clock (default enabled)
         -k nn                          Force rate correction for testing (+1 = add cycle, -1 = remove cycle)
         -l time_offset                 Set offset of time sent to UTC as per computer, +/- float hours
         -o time_offset                 Set IEEE 1344 time offset, +/-, to 0.5 hour (default 0)
         -q quality_code_hex            Set IEEE 1344 quality code (default 0)
         -r sample_rate                 Audio sample rate (default 8000)
         -s                             Set leap warning bit (WWV[H] only)
         -t sync_frequency              WWV(H) on-time pulse tone frequency (default 1200)
         -u DUT1_offset                 Set WWV(H) DUT1 offset -7 to +7 (default 0)
         -x                             Turn off verbose output (default on)
         -y yymmddhhmmss                Set initial date and time as specified (default system time)

This software licenced under the GPL, modifications performed 2006 & 2007 by Dean Weiten
Contact: Dean Weiten, Norscan Instruments Ltd., Winnipeg, MB, Canada, ph (204)-233-9138, E-mail dmw@norscan.com

Raspberry Pi integration

WIP

Thanks

Ivan B.

Thomas B.

Dean Weiten