View Full Version : Re: Analogue output Quality

2004-11-24, 10:56
Your information is not entirely correct.

Single mode fiber uses glass core and cladding and uses class I or II lasers
to transmit data. However, multi-mode fiber is basically just plastic and
uses nothing but cheap LEDs for light transmission. These connections are
easily capable of running high speed synchronized data in the 1000 megabit
or faster range.

-----Original Message-----
From: discuss-bounces (AT) lists (DOT) slimdevices.com
[mailto:discuss-bounces (AT) lists (DOT) slimdevices.com] On Behalf Of T
Sent: Wednesday, November 24, 2004 4:12 AM
To: discuss (AT) lists (DOT) slimdevices.com
Subject: R: [slim] Analogue output Quality

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

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.


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