tot;216769 Wrote: > > If the recovered jittery clock drives the DA conversion in the receiver > sure, jitter can and will lead to non-perfect waveform. I would naively > think that DAC's would do something better to be immune to bit-by-bit > jitter?
Well, it's not quite as easy as that. The most obvious thing is simply to have a good local clock in the DAC, and use that to clock out the bits. The problem is that the rate at which that clock runs will be slightly different than the rate at which the bits arrive. If it's faster the DAC buffer will empty; if it's slower the buffer will fill. Either way, bad. That's why DACs reconstruct a clock from the data itself. Still, it really doesn't sound like a very hard problem - all you need is a clock with the right average rate - and in fact PLLs do a pretty good job of generating a clean clock (they essentially smooth out the jitter by averaging over many cycles). However some claim that even the small amount of jitter than remains is audible, but it's apparently possible to do even better. For example the Benchmark DAC1 seems to be absolutely immune to input jitter (its output measures the same no matter how jittery the input). -- opaqueice ------------------------------------------------------------------------ opaqueice's Profile: http://forums.slimdevices.com/member.php?userid=4234 View this thread: http://forums.slimdevices.com/showthread.php?t=37044 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
