Il giorno 18/set/07, alle ore 15:50, Clemens Ladisch ha scritto: > John Rigg wrote: >> On Tue, Sep 18, 2007 at 10:07:05AM +0200, Ludovico Verducci wrote: >>> As far as I know the delta family boards drivers support the >>> synchronization of up to 4 audio boards over PCI: at the moment I'm >>> reverse engineering the hardware trying to understand how this >>> can be >>> accomplished. >> >> I'm aware that some Windows users are using several Delta 1010s >> without external sync, but I'm not sure how it is done (or how >> good it sounds). AFAIK it would require a VCXO so that the frequency >> of the card's clock could be varied by enough to keep it in sync >> (ie. making the clock oscillator part of a phase locked loop). >> Looking >> at the PCI card on the 1010, I can only see standard fixed-frequency >> crystals. The only PLLs appear to be the internal PLL in the S/PDIF >> receiver and the 4046 PLL chip for the word clock input signal. Yes, I agree. If there's a way to achieve this kind of synchronization it isn't simple, at first sight. I'm trying to reconstruct the board's schematics and studying components' data sheets to figure out a way to make it work. > In theory, it should be possible to use the PCI clock (between 25 and > 33 MHz) as input for one of the PLLs, probably after dividing it down. This could be also an option, but I really hope that the feature can be implemented in software because I surely cannot synch over ethernet the PCI clocks! Let's see... Regards, Ludovico _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
