ar-t;238344 Wrote: > It is inferior, and it is not a myth. You are grossly uninformed. > > Galvanic isolation can be achieved by using transformers, althoough > doing so requires some skill on the part of the designer. > > Of all the optical methods, TOSLINK is the worst. Single-mode fibre > could be used effectively, but alas, the way it is commonly implemented > is all wrong. > > (In case anyone actually cares, I helped to engineer the world's first > single-mode long-haul fibre system. I may just have an idea what I am > talking about. Not that the ignorant will care; they rarely are > open-mended enough.) > > Pat
I think you're over-analysing the behaviour of the TOSLINK connection, and making comparisons that don't really apply. Of course if you're considering long-distance high speed communications, then pulse spreading due to optical line width and multiple propagation paths along the fibre are significant. But over a few feet, running at 5.6 MHz? (As an aside - try looking up a data sheet for the type of high speed comparator used as a line receiver for coax. I bet you'll find a skew, which translates into data-dependent jitter, which is orders of magnitude greater than any spreading due to optical effects in the cable). What I do find surprising is that anybody designs a DAC that uses the SPDIF input as a timing reference rather that merely a source of bits. I've spent some of my spare time this year designing a DAC - based around the AK4396 as it happens - which makes no attempt to directly recover a clock from the SPDIF input. Incoming edges are used merely to identify where bits start and finish so they can be sampled correctly, nothing more. So, it's an inherent property of the design that input jitter makes no difference at all. Doing this is not expensive, and I don't regard the use of a crystal and an FPGA as "fancy". I do, however, regard the topology as "correct" - and, fortunately for those of us with a working design with commercial potential, "unusual". One day, all DACs will be made this way. -- AndyC_772 ------------------------------------------------------------------------ AndyC_772's Profile: http://forums.slimdevices.com/member.php?userid=10472 View this thread: http://forums.slimdevices.com/showthread.php?t=33146 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
