Racer-X@saturn.ucc.umass.edu (Chris Lloyd) (10/02/90)
I'm posting this in comp.sys.next and sci.electronics because its
sort of a cross-breed question..
I just purchased a new SONY CD (music) player the other day, this player
has a fiber optic digital output. I'll be ordering a NeXT Slab within
a few months. What I'm wondering is, seeing as how the sound coming out
of my CD player is already digitized.
Is there anything out there that will take this feed and pump it
into a NeXT? any computer?
How difficult would it be to build such a device? can I get the
parts?
Does anyone have information on this type of interface?
I think it would be really nice to feed super clean digitized sound
from a CD player to the NeXT where it can me manipulated in CD quality
and then pumped out to a amp. Maybe I wont have to buy an equalizer :)
Thanks in advance, if I get any information I'll summarize to the net...
--
Chris Lloyd - Racer-X@saturn.ucc.umass.edu
"Got a big white X, on the top of his car..." - Big Black
mackenzi@Apple.COM (Steven MacKenzie) (10/06/90)
My question is ... why would any one want to use fiber optic to transmit digital data 6 feet or so? The difference in error rate of fiber vs. wire for such a small distance must be negligible. Sounds like a very expensive solution for a non-problem. Steve MacKenzie, mackenzi@apple.com #include disclaimer.std
jgd@rsiatl.UUCP (John G. DeArmond) (10/08/90)
mackenzi@Apple.COM (Steven MacKenzie) writes: >My question is ... why would any one want to use fiber optic to transmit >digital data 6 feet or so? The difference in error rate of fiber vs. wire >for such a small distance must be negligible. Sounds like a very expensive >solution for a non-problem. Oh, I don't know. Six feet is about right to keep nasty 'ole Mr. Lightning out of the hardware goodies. Pretty fair tradeoff, wouldn't you say. A $5 LED sacrificing itself for a multi-kilobuck computer. <cheap-shot alert on - I just can't pass the opportunity> I can understand how that would not be obvious, comming from an Apple site. After all, according to a Mac zealot friend of mine, AppleChat is DC coupled which reacts nicely to unbalanced neutrals in a building. He's got smoked couples to show for it. I wouldn't know myself, having never touched the things. <cheap-shot off> :-) John -- John De Armond, WD4OQC | We can no more blame our loss of freedom on congress Radiation Systems, Inc. | than we can prostitution on pimps. Both simply Atlanta, Ga | provide broker services for their customers. {emory,uunet}!rsiatl!jgd| - Dr. W Williams | **I am the NRA**
brian@ucsd.Edu (Brian Kantor) (10/08/90)
mackenzi@Apple.COM (Steven MacKenzie) writes: >>My question is ... why would any one want to use fiber optic to transmit >>digital data 6 feet or so? The difference in error rate of fiber vs. wire >>for such a small distance must be negligible. Sounds like a very expensive >>solution for a non-problem. It's a nifty way to keep RF in or out of the box. Tempest-style vaults use fiber to get the telephones past the shielding. - Brian
vermilye@Oswego.EDU (Jon R. Vermilye) (10/09/90)
In article <10596@goofy.Apple.COM> mackenzi@Apple.COM (Steven MacKenzie) writes: > >My question is ... why would any one want to use fiber optic to transmit >digital data 6 feet or so? The difference in error rate of fiber vs. wire >for such a small distance must be negligible. Sounds like a very expensive >solution for a non-problem. > >Steve MacKenzie, mackenzi@apple.com >#include disclaimer.std I didn't catch the original article, however there are a few reasons for using fiber over wire... One of the reasons is to prevent EMI/RFI problems. Even though it is a short distance, there is no need for shielding. Longer fiber optic cables are sometimes used for sound reinforcement systems to prevent problems with electrically noisey lighting dimmers. If security is a problem, another advantage is the difficulty tapping into fiber. Jon R. Vermilye 315 341 2138 Department of Theatre, Tyler Hall vermilye@oswego.oswego.edu SUNY Oswego ..rutgers!sunybcs!oswego!vermilye Oswego, NY 13126 vermilye@snyoswva.bitnet
kravitz@foxtail.UUCP (Jody Kravitz) (10/10/90)
>mackenzi@Apple.COM (Steven MacKenzie) writes: >>>My question is ... why would any one want to use fiber optic to transmit >>>digital data 6 feet or so? The issue here it so keep the (unconverted) digital signal out of the audio. The clock rate in the cable is 44,100 * 2 * (16 bits + framing). Thats about 1.5MHz. Fast rise times and TTL signal levels would invite coupling to any nearby low-level audio circuit (tape monitor, graphic EQ, etc). The fiber-optic cable guarantees this won't happen.
whit@milton.u.washington.edu (John Whitmore) (10/11/90)
In article <314@foxtail.UUCP> kravitz@foxtail.UUCP (Jody Kravitz) writes: >>mackenzi@Apple.COM (Steven MacKenzie) writes: >>>>My question is ... why would any one want to use fiber optic to transmit >>>>digital data 6 feet or so? > >The issue here it so keep the (unconverted) digital signal out of the >audio. The clock rate in the cable is 44,100 * 2 * (16 bits + framing). Thats >about 1.5MHz. Fast rise times and TTL signal levels would invite coupling... Actually, the fast-rise signals are created deliberately, at each end of the transfer, anyway. And, the straight 'eye pattern' off the photodiode detector is bandwidth limited, so would be trivial to buffer and send (through a transformer if you want to keep current loops out of the picture) to any other box. Additionally, optical links don't develop good bandwidth on short cables (oddly, the attenuation in the cable is necessary to keep high-frequency 'ringing' from occurring in the fiber link); in short, the optical link has NO advantage over simple balun/twisted pair wiring. The decision, IMHO, was simple gee-whiz marketing. Someone said to a group of engineers, 'What can we offer the customers, that our competition will take months or longer to match?' I am known for my brilliance, John Whitmore by those who do not know me well.