opaqueice;153828 Wrote: > However, there is another, entirely different approach possible, which - > as far as I can see - completely and totally eliminates the effects of > input jitter. This does not use a PLL at all, because it does not > reconstruct the clock from the incoming data stream. As I said above, > simply imagine having a huge buffer in your DAC. Now run the audio > stream for, say, one hour (the length of a CD). Record the entire > thing in the buffer. You now have it stored as a digital sequence > which (barring bit errors) is identical to the sequence on the CD, and > has nothing at all to do with any jitter in the S/PDIF signal that > carried it. Now, after waiting one hour, you get to listen to your > jitter-free music as the DAC plays out the data, using its own internal > crystal clock (which can be extremely clean). > > Not very convenient, because you had to wait so long, but this totally > eliminates the effects of transport jitter (if not, I'm waiting for > someone to tell me why). Now since this is rather inconvenient, you > can be more clever and reduce that initial wait from one hour to a > nearly imperceptible pause, and that's what the Lavry does (according > to their white paper). This does not use a PLL because it does not > reconstruct the clock from the incoming S/PDIF - it uses its own clock > - and therefore I fail to see how it can be affected by jitter.
This is essentially a FIFO buffer (my Dodson DAC does the same thing, albeit with a much bigger buffer than the Lavry), and in this architecture, you need to deal with things like buffer overflow/underflow, because the data is still "streaming"...and this still requires some "cooperation" between the incoming clock and the re-clocker. This will still contain some inherent jitter. The only way to truly do it without a master/slave architecture is to completely load the audio data into solid state memory up front, so there is no buffer management required. There is a player that does this called the Nova Physics Memory PLayer... -- PhilNYC Sonic Spirits Inc. http://www.sonicspirits.com ------------------------------------------------------------------------ PhilNYC's Profile: http://forums.slimdevices.com/member.php?userid=837 View this thread: http://forums.slimdevices.com/showthread.php?t=29450 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
