Tom Van Baak wrote: > Could you sync the sounds cards in software? > > If you feed an external 1 PPS into the unused stereo channel of > each sound card, then you can solve both card-to-card phase > differences as well as card-to-card frequency differences with > simple software fitting after, or even while, samples are being > collected. > > I use the R-channel for my 1PPS timing, leaving the L-channel > for analog input. A time-synced PC can resolve the seconds > time-of-day ambiguity. > > Note that a sharp 1pps will give you 22 us (1/44100) precision. > If you used a slower ramp'ed 1pps then software interpolation > should give you sub-microsecond precision. > > If you want to measure the stability of your sound card, see: > http://www.leapsecond.com/pages/sound-1pps/ > > Win32 source code to the tool is very simple; see: > http://www.leapsecond.com/tools/1hz.c > > /tvb > A higher sync frequency than 1Hz, say around 100Hz or so is probably desirable for better cancellation of sampling clock phase noise.
Bruce _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
