I don't know if they've been discontinued, but a number of the M-Audio cards had word clock inputs as well. They are/were pretty widely available on eBay. John On 7/6/2012 11:24 AM, Azelio Boriani wrote: > OK, found it: the RME HDSPe RayDAT PCIe audio card has this reference but > with the optional extension card (of course). It is $950 for the card + the > expansion card for the world clock... > > On Fri, Jul 6, 2012 at 5:09 PM, Jim Lux <jimlux@earthlink.net> wrote: > >> On 7/6/12 7:51 AM, Azelio Boriani wrote: >> >>> Yes, I'm also interested in how-to. At the moment I think it is a hack: >>> there is no sound card AFAIK that accepts a reference input. I have >>> recently bought an Acqiris/Agilent DP105/U1067A 150MHz 500Ms/s digitizer >>> PCI card that accepts an external 10MHz as a reference for the sampling >>> process. >>> >>> >> oops I was wrong.. there ARE people making PCI multichannel audio >> interfaces with external clock.. RME in Germany makes more than one. >> >> >> >> >> ______________________________**_________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/** >> mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> >> and follow the instructions there. >> > _______________________________________________ > 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. >

A few cards accept a reference clock in the MHz range (usually under the term "Superclock"), but most wordclock inputs are made for the wordclock frequency itself, for example 48 kHz. An internal PLL (of varying quality) multiplies that up to a multiple of it for driving the converter and shift clocks. Those PLLs often have a rather wide lock range, so you'd be able to feed 50 kHz (or 100 kHz or 200 kHz) into it, which can be divided down from 10 MHz quite easily. Not sure whether that's what you want, however. Cheers Stefan > -----Ursprüngliche Nachricht----- > Von: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] Im > Auftrag von John Ackermann N8UR > Gesendet: Freitag, 6. Juli 2012 16:58 > An: Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] Allan Deviation question > > I think a number of higher-end sound cards accept a "word clock" or > "world clock" (I've seen it both ways) that's intended to allow syncing > to an external source. The challenge I've seen is that the frequency > (either in the 12 or 24 MHz range) is one that's not simple to > synthesize precisely (i.e., zero offset from nominal) and with low > jitter/phase noise from a 5 or 10 MHz reference. > > I think it would be a great project to come up with a synthesizer block > that could do that. It's been on my list for a long time, but hasn't > yet risen near the top. > > John > ---- > > On 7/6/2012 10:51 AM, Azelio Boriani wrote: > > Yes, I'm also interested in how-to. At the moment I think it is a > hack: > > there is no sound card AFAIK that accepts a reference input. I have > > recently bought an Acqiris/Agilent DP105/U1067A 150MHz 500Ms/s > > digitizer PCI card that accepts an external 10MHz as a reference for > > the sampling process. > > > > On Fri, Jul 6, 2012 at 4:43 PM, Stewart Bryant <stewart@g3ysx.org.uk> > wrote: > > > >> ... and running it to a sound card (oscillator gps disciplined) > >> > >> How did you achieve this? > >> > >> Thanks > >> > >> Stewart > >> > >> > >> > >> ______________________________**_________________ > >> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to > >> https://www.febo.com/cgi-bin/** > >> mailman/listinfo/time-nuts<https://www.febo.com/cgi- > bin/mailman/listi > >> nfo/time-nuts> > >> and follow the instructions there. > >> > > _______________________________________________ > > 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. > > > > > > _______________________________________________ > 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.

Removed the oscillator and send it the required freq (24.576MHz) that is disciplined to 10MHz. Put an sma connector next to the card in the little cover on the pci slot. Currently using my ds345 but am getting a Valon Synthesizer board with a divider. Tried ve1alq but the dividers aren't right and can't seem to fix that. Have a vcxo but no way to discipline it. Just going to break down and go the Valon route. Will also use it for 125MHz for my qs1r. Have done this setup with 2 sound cards. One is a SB xfi surround USB and the other is fata1ity extreme gamer. Works like a charm for both. 20uHz plus minus through my radio (with 10MHz signal) Should be much better with audio but can test because my ds345 is tied up. I would bet I will have substantially sub-uHz precision is the audio only domain. Doc KX0O Sent from my iPhone On Jul 6, 2012, at 9:43 AM, Stewart Bryant <stewart@g3ysx.org.uk> wrote: > ... and running it to a sound card (oscillator gps disciplined) > > How did you achieve this? > > Thanks > > Stewart >

OK, I'll take a look at my cheap audio cards searching for the oscillator. On Fri, Jul 6, 2012 at 5:59 PM, Bill Dailey <docdailey@gmail.com> wrote: > > Removed the oscillator and send it the required freq (24.576MHz) that is > disciplined to 10MHz. Put an sma connector next to the card in the little > cover on the pci slot. Currently using my ds345 but am getting a Valon > Synthesizer board with a divider. Tried ve1alq but the dividers aren't > right and can't seem to fix that. Have a vcxo but no way to discipline it. > Just going to break down and go the Valon route. Will also use it for > 125MHz for my qs1r. > > Have done this setup with 2 sound cards. One is a SB xfi surround USB and > the other is fata1ity extreme gamer. Works like a charm for both. 20uHz > plus minus through my radio (with 10MHz signal) Should be much better with > audio but can test because my ds345 is tied up. I would bet I will have > substantially sub-uHz precision is the audio only domain. > > Doc > KX0O > > > Sent from my iPhone > > On Jul 6, 2012, at 9:43 AM, Stewart Bryant <stewart@g3ysx.org.uk> wrote: > > > ... and running it to a sound card (oscillator gps disciplined) > > > > How did you achieve this? > > > > Thanks > > > > Stewart > > > > _______________________________________________ > 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. >

On 07/06/2012 04:58 PM, John Ackermann N8UR wrote: > I think a number of higher-end sound cards accept a "word clock" or > "world clock" (I've seen it both ways) that's intended to allow syncing > to an external source. The challenge I've seen is that the frequency > (either in the 12 or 24 MHz range) is one that's not simple to > synthesize precisely (i.e., zero offset from nominal) and with low > jitter/phase noise from a 5 or 10 MHz reference. > > I think it would be a great project to come up with a synthesizer block > that could do that. It's been on my list for a long time, but hasn't yet > risen near the top. A correct word clock should run at sample rate, i.e. 48 kHz or 96 kHz, which isn't stellar in synthesis difficulty. For description of Word Clock, please see Appex B in AES 11. There are system clocks also being used, typically x128 of the sampling rate, so 6.144 MHz, 12.288 MHz and 24.576 MHz hence is popular. Again not stellar to lock. Cheers, Magnus

On 07/06/2012 05:09 PM, Jim Lux wrote: > On 7/6/12 7:51 AM, Azelio Boriani wrote: >> Yes, I'm also interested in how-to. At the moment I think it is a hack: >> there is no sound card AFAIK that accepts a reference input. I have >> recently bought an Acqiris/Agilent DP105/U1067A 150MHz 500Ms/s digitizer >> PCI card that accepts an external 10MHz as a reference for the sampling >> process. >> > > oops I was wrong.. there ARE people making PCI multichannel audio > interfaces with external clock.. RME in Germany makes more than one. digital audio => need to lock clocks. Long ago existed audio boards which sample rate converted (badly) digital audio, this proved to be a killer for pro apps. With digital audio you need to control your clocking and have things tied to a master, especially when having multiple sampling boxes. etc. The analogue world was so much easier in this regard... Cheers, Magnus