DCtoDaylight;344532 Wrote: > Unfortunately, this looks like an example of a wiki that is wrong and > needs editing.... > > The SPDIF and AES/EBU interfaces have -always- encoded the clock into > the bit stream. > > It's also wrong in the underlying premise. Jitter is always present, > both in independent clock transmissions, and in encoded transmissions. > The reason an independent clock is preferred, is that it removes > sensitivities to data patterns in the clock recovery circuit. In other > words, it's possible for your favorite music to increase or decrease > jitter in an encoded clock transmission!
Okay, I get that. English isn't my first language so try to follow me here: I think the terminology is the problem. In synchronous data-transmission, the clock isn't really encoded within the data that's transmitted... but you can recover the clock from the data-stream because it's transmitted synchronously with the clock of the transmitter. That clock you retrieve should be a clone of the clock of the transmitter but it isn't exactly because of all we discussed. I agree to that. But this problem can be eliminated as follows: You receive SPDIF synchronously and it's easy to do that without bit-errors. The clock that you can retrieve from the datastream is only used for receiving that stream, and examined on it's -intended- rate, like 44.1 or 48 kHz. That's where this "clock" ends, it's discarded for further processing. At this point you have a digital audio representation (unclocked but you know it's sample-rate) that you could save on a hard-disk as WAV file, right? Next, you can generate your own clock with your own/local oscillator and re-clock the data with that before sending it into the DAC chip. This would eliminate the problem, won't it? I don't know what they do, maybe they don't believe anyone can hear the jitter? I'm just trying to understand why jitter is still a problem. I know they can measure it now, so it's really there, and I also believe that an optical link introduces more jitter than coaxial, but I still do not believe that the difference that people hear between the two is -caused- by that difference in jitter. I see no prove of that and find it much more plausible that the difference as experienced by those people is from an analog cause like the electrical ground connection that you have with coax but don't have with fiber. That is why I would propose to test using fiber both with and without an -unused- coax-cable attached. My idea is that using optical with "coax cable connected too" may sound the same as using coax? What I really don't believe is that people can hear a difference between a glass and a plastic optical cable if both are good assembled cables. cheers, Nick. -- DeVerm ------------------------------------------------------------------------ DeVerm's Profile: http://forums.slimdevices.com/member.php?userid=18104 View this thread: http://forums.slimdevices.com/showthread.php?t=52817 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
