Steve, I certainly agree with everything you have said, except that I'm curious as to why the optimal cable length for USB would be similar to what is optimal for S/PDIF. The rationale for 1.5 meters that is presented in your paper is based on the presumption that signal risetimes and falltimes are in the vicinity of 25 ns. Aren't risetimes and falltimes far faster than that for USB 2.0, and therefore why would the optimal cable length for the two kinds of interfaces be similar?
Regards,
-- Al
Regards,
-- Al