[time-nuts] Timestamping audio waveforms

[Tim Shoppa]

I would like sub-millisecond timestamps for a mono audio radio signal that
I have in the shack.

The timestamps could be continuous (Every sample) or just every "frame"
where maybe a frame is a second to a minute.

I would like to calibrate both the absolute time as well as the delta time
between samples based on the timestamps. (I would expect that say a nominal
48kHz sample rate would be off by many tens of ppm because of crystal
tolerances.).

I have a both Windows and Linux based PCs running Audacity with a local
GPS-based LAN refclock and ntpd. I trust the ntpd time to be stable to the
sub-millisecond.

Can Audacity do this kind of timestamping for me based on the system clock?

Or should I, say, take the PPS from a GPS, and feed it into channel 2, with
the audio going into channel 1, and make a stereo recording? I suppose I
could then manually label the filename with the second the recording was
begun. There would likely be some delta (maybe half the sample interval?)
between the two channels but I'm fine with that as long as it is at the
sub-millisecond level.

Tim N3QE