Pat, I am not sure I agree on jitter. My simplistic view of a digital audio stream is that if plotted on a graph, the 'y' coordinates are provided by the digital amplitude of the sample, the 'x' coordinates are implied by the (assumed) regular sample period. So to plot a point on the graph accurately, you need to have both x and y coordinates correct. Having the sample at the wrong time is just as bad as having a sample that is the wrong size.
I suppose the real question is whether the level of jitter experienced in the clock derived from S/PDIF is in any way significant from an audio perspective. If my maths was up to it, I could probably take a jitter distribution and convert it into either an implied noise or a distortion figure in the derived audio signal. I would then be able to see how many picoseconds of jitter mattered or whether this is negligable. Any link to analysis on this would be welcome. If the NAIM ring buffer approach catches on then I guess this all becomes irrelevant. In the scheme of tricky hardware, reading in a jittered signal into a ring buffer and reclocking out at a stable rate with a local accurate clock is pretty basic. It feels like something that could be very easily and cheaply implemented in all external DACs. To put this in perspective, and again at the risk of showing my age, I have seen timebase correctors that performed a very similar function de-jittering a video signal built using delay lines that dated from the 60s. For an even older example, I have recently visited the telegraph museum at Porthcurno in Cornwall where they have on display a reclocking system that takes a jittered high speed morse signal from a transatlantic cable, derives a clock from the incoming data, resamples and de-jitters - and this is pre second world war and built with gears, motors and switches. To be fair, neither approach could cope with much jitter, and neither had the luxury of large ring buffer storage, but it goes to show that there is nothing new under the sun. -- Andy8421 ------------------------------------------------------------------------ Andy8421's Profile: http://forums.slimdevices.com/member.php?userid=16846 View this thread: http://forums.slimdevices.com/showthread.php?t=70626 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
