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T
2004-11-24, 04:11
If the interfaces are correctly desighned, there will be absolutely
no difference between an electrical or optical SPDIF link. Of
course, using a poor quality PLL at the receiver end will tend to
allow any jitter to show up in the audio, but a good quality PLL will
eliminate it.

In my experience, real-world optical SPDIF interfaces are however
inferior to electrical SPDIF interfaces due to the fact that optical
SPDIF liks use the TOSLINK stuff, which is terribly non-sysmetrical
when converted back to electrical. These use visible (i.e. plain old
ordinary red) LEDS rather than the laser-diodes used in professional
audio and communication equipment.

Note that in any case, SPDIF whether optical or electrical is not
designed for link lengths of more than several feet, and thus will
produce a lot of errors at longer distances. If you want to go
farther (400m or so), an AES-EBU balanced link will work perfectly
well, further and you will nead an optical link using laser diodes.

Tom

P.S. Yes, I design this stuff for a living.