Soulkeeper;683632 Wrote: > S/PDIF uses 'Differential Manchester encoding' > (http://en.wikipedia.org/wiki/Differential_Manchester_encoding) aka > biphase mark code. From Wikipedia: "A transition is guaranteed at least > once every bit, allowing the receiving device to perform clock > recovery." I guess this is part of the reason why any decent DAC can be > regarded as immune to input jitter. > > I also found an interesting little article, 'How does jitter sound?' > (http://www.jitter.de/english/soundfr.html) which states (very > plausibly) that DAC jitter is most audible in the higher frequencies. > > I did not find anything about exactly how DACs convert the Manchester > encoded signal to an analog sound wave (I guess this also differs to > some degree). It would be interesting to trace the signal path and see > what behaviour, if any, that can be predicted from it. If you are interested in this I recommend Watkinson http://www.amazon.co.uk/Introduction-Digital-Audio-John-Watkinson/dp/0240516435
I am not an engineer but got bored listening to BS from people who have no idea what they are talking about. So I read this book and the one by Pohlmann and Jim Lesurf's information and Measurement. The simplest explanation of how a dac works is that it samples and holds. So if the sample value is 10 it produces a voltage equal to 10x LSB value which it holds until the next sample is coverted. This produces a staircase pattern ie a series of square waves. It is demontsrable that this wave equals the orginal sample value plus images at higher frequency. Thus when you apply the anti imaging filter with a stopband at nyquist you remove the images- and hey presto the resulting analog signal equals the orginal band limited signal (ie the signal sampled in the ADC at the recrding studio). see http://www.lavryengineering.com/forum_images/Digital_Audio.pdf and the other articles on the same website which are very good indeed. -- adamdea ------------------------------------------------------------------------ adamdea's Profile: http://forums.slimdevices.com/member.php?userid=37603 View this thread: http://forums.slimdevices.com/showthread.php?t=92918 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
