Why aren't we using analog light for interconnects
Jul 25, 2008 at 2:43 PM Thread Starter Post #1 of 15

Oublie

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hi,

I've just been refreshing my knowledge on AC power etc (about 25yrs since i looked at this) and something struck me that maybe some of you guys might be able to answer.

Given that generally these days a lot of us are using a digital source and using some form of digital to analog converter and the fact that everyone seems to be searching for the holy grail of the perfect interconnect why aren't we using some sort of analog light transmitter and receiver mated to high quality fibre optic cable for interconnects. No voltage no real interference all the bandwidth you would ever need and mated to a transmitter (read superfast variable light source) connected via fibre to a receiver capable of extremely high resolution reading of the light source which it then converts to the necessary voltages.

Has this been done? does it work? or am i just being silly?
 
Jul 25, 2008 at 3:19 PM Post #3 of 15

Oublie

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Quote:

Originally Posted by threEchelon /img/forum/go_quote.gif
There is some high end interconnect I've seen that converts an electrical audio signal to light and then back again.


Cool just found a link to one http://www.harmonictech.com/docs/har...ual_031507.pdf has anyone every tried such a thing and if so are they any good?
 
Jul 25, 2008 at 3:26 PM Post #4 of 15

ruZZ.il

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I've never tried it, but I could think of a bunch of hurdles that need to be jumped over... though, hurdles are made to be jumped over.
 
Jul 25, 2008 at 3:45 PM Post #5 of 15

progo

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I'd think binary signal is easily read by photodiodes that don't have much accuracy, but enough to spot whether there's bright light coming, or not. Analog signal would require thousands of these diodes unless there's a pot that would work in similar manner. I don't think it'll be possible.

That pdf.. the cables look very interesting. And they need extra power! Maybe it converts the voltage changes into sound-like pulses and vice-versa.
 
Jul 25, 2008 at 4:26 PM Post #6 of 15

nikongod

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with few exceptions i think the "faults" to be found in the conversion from electcrical to light, and back will swamp the problems of all but the absolutely longest cables.

you are adding a MINIMUM of 2 active components directly to the signal path with this, and from their descriptions probably more.

It could work to an advantage over exceptionally long cable runs: ie more than 50yards.
 
Jul 25, 2008 at 5:04 PM Post #7 of 15

rds

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Quote:

you are adding a MINIMUM of 2 active components directly to the signal path with this, and from their descriptions probably more.


On top of that there are all sorts of refractive issues causing dispersion of the signal, as well as limitations from the emitter and receiver. Sounds like audiofool nonsense to me, but I could be wrong.
Also, I'd like to one example where "audiophile technology" has preempted developments in telecommunications.
 
Jul 25, 2008 at 5:10 PM Post #8 of 15

Uncle Erik

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You would still need an amp with electricity at the end, wouldn't you? Unless someone develops a transducer that can be driven by light only (wouldn't that be cool?) you're just going to shift the issues closer to the driver.
 
Jul 25, 2008 at 6:44 PM Post #9 of 15

Oublie

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I think all your points are valid guys

complexity i.e. additional components is definately a factor as would be refraction etc.

On the other hand if the positives outweigh the negatives then we would certainly have a better cable.

I heard that ibm have developed light processing technology at a nanometer leve l for digital computers etc but since the medium used is by default analog i just thought i'd ask. (sometimes my brain goes sideways
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This is mostly gueswork but i'm thinking highspeed variable intensity laser with the facility to transmit the relevant ac data at variable light intensities sending to a photoelectric cell which by its nature generates voltage (amplitude based on light intensity?) followed by the relevant amplification. Also if the light could change colour relevant to frequency and this too could be received and analysed maybe its a general idea of how it works
 
Jul 25, 2008 at 6:53 PM Post #10 of 15

Uncle Erik

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You have to convert the light to electricity somewhere along the chain. Unless you couple the amp directly to the transducer, you will have to use an electrical run of wire somewhere.
 
Jul 25, 2008 at 7:46 PM Post #11 of 15

nikongod

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an idea that jsut came to light:
In digital sources the "direct" electrical SPDIF output often sounds better than the optical output, which is the electrical signal converted to light and back in the digital domain...
 
Jul 25, 2008 at 8:57 PM Post #12 of 15

gyrodec

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Stereophile reviewed these interconects. MF loved the sound, but they measured very badly for a cable, i.e. these WAS measureable distortion and noise. You don't normally get measurements on an interconnect, because for a normal length at audio frequencies there really isn't anything that can be measured in terms of noise or distortion. I don't think you could get the noise and distortion of these analog light calbes down to normal copper/electrical cable values, even over very long runs in noisey environments (espcially against balanced drvie).
 
Jul 25, 2008 at 9:22 PM Post #13 of 15

majid

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Some of the earliest recording methods used photographic rather than electrical methods. Movie sound tracks also used to be optically encoded in the bits of film between sprocket holes. What nobody has done (AFAIK) is a pure optical to audio transsducer.
 
Jul 26, 2008 at 9:20 AM Post #14 of 15

Jingo Lingo

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Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif
You have to convert the light to electricity somewhere along the chain. Unless you couple the amp directly to the transducer, you will have to use an electrical run of wire somewhere.


This is why I don't understand what the deal with cables is. Unless your entire amp is wired with the same stuff used in your interconnect, aren't any sonic benefits going to be lost?
 
Jul 26, 2008 at 10:09 AM Post #15 of 15

Quaddy

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it will happen somewhere 'down the line'

i have been playing with lasers of late and trialling sending music/voice data down the laser DIY style, kind of like enforcing your music on someone remotely
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and then i got in to the laser wireless big guns online forums etc, and there are firms which already use that technology (since 90's) to deploy high band wireless via laser to large communities which are remotely located or need the wireless aspect of it, very interesting technology wtih amazing offshoots and application at almost every branch.

cant wait for the future to arrive!

just thought this was coincidental and similar to what i had been looking at, i guess there are those who are always going to want good old fashioned wired cables, and cable firms will probaly attempt to discredit, or at worst kill th epeople who get this up and running! like the guy that claimed he had used water for fuel!
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disappeared of the face of the earth!
 

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