Add balanced inputs to the list of desirable features. Bruce Don Latham wrote: > 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 -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > >
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