Yes, they make TDRs for coax and optical systems. It was 25 years ago when I did fibre, so getting an optical TDR to work was a pain. The centre core was so far off of centre that it made getting a good coupling very difficult. (Obviously, they eventually figured out how to pull fibre, and it is pretty easy today.)
OK, a VSWR of 1.1:1 should work fine for a VHF radio, but I can assure you SPDIF sounds not so good at that level. SPDIF is rather odd in this respect. Probably the most sensitive interface around. In the case of your radio, the insertion loss from that amount of return loss is very small. Some frequency-dependent component, but fractions of a dB at best. With SPDIF, it is not an insertion loss problem. Pulse dispersion is a problem, but a lot of that comes from having to pass EMC standards. (It takes around 50 MHz to make it sound good. 100 MHz is better.) The main problem is the jitter that occurs in the clock recovery. And it still sounds bad. Remember, not everyone has a D/A box that goes to the lengths necessary to address its shortcomings. Pat -- ar-t http://www.analogresearch-technology.net ------------------------------------------------------------------------ ar-t's Profile: http://forums.slimdevices.com/member.php?userid=13619 View this thread: http://forums.slimdevices.com/showthread.php?t=52817 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
