On this track, what's the group opinion as to the best USB sound "card"? I'm looking for one for time as well as sd radio use. Should have the best separation, best s/n, highest digitization rate, 24 bit, etc. Any recommendations? Thanks Don
Bruce Griffiths > 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. > -- Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com _______________________________________________ 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.
