> -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Magnus Danielson > Sent: Tuesday, June 02, 2009 10:08 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Sound Cards for locking to GPSDO 10 > MHz references > > > > > > > Some of the "pro" sound interfaces have a "word clock" input. > > > > There are a variety of things that take a external input > and generate a S/PDIF that's properly timed, as well. Lots of > boxes will take a S/PDIF sync input (e.g. the Edirol FA-66 > which was used by lots of Flex-Radio folk), so maybe that's > something you could easily generate from your 10MHz. > > > > A chart at Cakewalk shows that MOTU has a USB interface (828MkII) > > which has a word clock sync. It's going to be a pricey > beast though, > > with 8in/8out ($800?) > > > > Even if you have a word clock input, you're going to have to > > synthesize that from the 10 MHz. Maybe it's easier to just make a > > S/PDIF which is a MUCH more common sync signal. ( I think S/PDIF is > > something like 3 MHz) > > S/P-DIF [iec60958-3] has a baudrate which is 128 x sample > rate and a bit rate which is 64 x sample rate, which is > inherited properties from AES/EBU [aes3] [tech3250] [iec60958-4]. > > Locking up a S/P-DIF (128 x sample rate) is about the same > job as locking up a superclock (256 x sample rate) or > wordclock (1 x sample rate).
However, if you're buying an off the shelf audio interface, you're stuck with whatever the mfr is providing for a sync input, and a (very) casual inspection of what's available these days (particularly at low cost) shows that S/PDIF seems to be the most common. _______________________________________________ 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.
