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Hi Grover,
You're making the same errors as I made once....
(1) The optical cables used for TosLink aren't fiber optic cables. They use a
light conducting plastic.
(2) The supported frequency is about 6Mbit/sec. Fiber optic connections in data
and
telecomunication (like an FDDI backbone) go beyond 100 Mbit/sec.
(3) The length of the cable... TosLink is in most cases shorter than 2 meters.
In telecomunications, optical connections are usual longer than 100 meters (
The limit for CAT5).
Cheers,
Ralph -> You can't compare apples and oranges (and both are fruits!)
[EMAIL PROTECTED] wrote:
>
> There can indeed be differences in fiber optic cables. The question is
> whether or not these differences will affect the sound. (I worked in the
> telecommunications and broadacst industries for many years teaching, amongst
> other things, fiberoptics.)
>
> The differences between "quality" and lesser cables will usually be
> mechanical, but this is not limited to quantification of strength. The
> problem with cables of poor quality may be their alignment within the
> connector housing. If the cables are misaligned, then the level of optical
> signal will go down. At some point, when the received signal is attenuated
> far enough, the bit error rate (BER) of the signal begins to increase and
> artifacts begin to show up in the recovered signal. Exactly what the
> receiving device does with digital signals in which there is a significant
> BER, depends upon the digital circuitry within the device.
>
> Another issue is that the fibre simply does not make a close coupling with
> the receiving diode because it is too far back in the housing. One of the
> demonstrations I used was to slowly attenuate the optical signal by pulling
> the cable out and watching the BER meter, at the same as listening to the
> recovered audio. Indeed, at some point the audio will become distorted and
> eventually disappear.
>
> Now will this in reality affect your audio signal? Attenuation of the
> optical signal due to misalignment or poor coupling might be a problem, but
> at the distances involved in out systems, there is plenty of overhead and it
> shouldn't have any affect. Additionally we are talking about our multimode
> optical cable, and alignment is simply not as critical as with the
> long-distance, high-bandwidth singlemode cables that are used in the
> broadcast and telecom industries.
>
> If you are really anal about all of this, then run this test: play through
> the optical cable and listen carefully as you slowly pull the optical
> connector (either end will do) out of the receptacle. You will probably be
> able to get a tenth of an inch out before you begin to lose the signal,
> maybe more. If you are getting a signal when you start this little test and
> you can move the connector out even a little and still get a signal, then
> you have enough optical power getting to the receiver.
>
> If you are really, really concerned, then you can always clean the ends of
> the cable with denatured alcohol. (Send pictures - I'd like a good laugh.)
>
> What this all really means is that you shouldn't worry about it. Enjoy the
> music.
>
> Iechyd da (that's "good health" in Welsh),
>
> Grover Cleveland
> www.llareggub.com
>
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Ralph Smeets Functional Verification Centre Of Competence - CMG
Voice: (+33) (0)4 76 58 44 46 STMicroelectronics
Fax: (+33) (0)4 76 58 40 11 5, chem de la Dhuy
Mobile: (+33) (0)6 82 66 62 70 38240 MEYLAN
E-Mail: [EMAIL PROTECTED] FRANCE
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We learned to talk."
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