"digital" is NOT digital

[spidey07]

You can't have an instantaneous state transition. There's this thing called time.

Especially with digital transmission. It's been a good 15 years since I've looked at the timing diagrams, but last I heard there are numerous encodings/framing/clocking/etc.

AFAIK, PCM audio has no error check. It isn't packetzed, but it is framed.

That is all. So let the smart EEs chime in.

In question is the very poor specs of TosLink. It's been a while since I looked at it but simple physics (core, wavelength) limit its bandwidth

-edit- thx for the correction sm8000.

 

[FoBoT]

:thumbsup:

i thought i had accidentally clicked on "highly technical" for a minute

 

[SlitheryDee]

Is this a multiple choice question? No it isn't.

 

[Steve]

"instantaneous"

 

[spidey07]

Originally posted by: FoBoT


:thumbsup:

i thought i had accidentally clicked on "highly technical" for a minute

It'll get more exposure here and hopefully will have some good posts. I don't proclaim to be a super EE guy as I got out of school 14 years ago. But there have been some very good posts on this subject in OT.

I merely want to dispel the "digital is digital" myth.

 

[KLin]

What is HDMI FTW? I'll take Home Theater for 800 Alex.

 

[UncleWai]

There's no 4th dimension, God doesn't exist.

 

[edro]

Who are you arguing with?

Isn't this common sense?

 

[spidey07]

Originally posted by: edro
Who are you arguing with?

Isn't this common sense?

You'd think.

But there is a mass misinformation amoung most people that "it either works or it doesn't" when it comes to digital transmission. That is what I want to spark the conversation about. I've seen some very good posts on OT that know exactly what I'm talking about but can articulate it much more intelligently than I.

 

[biggestmuff]

Originally posted by: edro
Who are you arguing with?

Isn't this common sense?

It is and I've backed up Spidey and other knowledgeable posters in similar threads.

I believe this thread is Spidey's response to this ongoing, reoccurring subject and also to my post questioning something he said in this thread..

 

[Tom]

on the subject of time, is time faster than the speed of light ?

seems like it would have to be, or nothing would ever happen.

 

[Iron Woode]

Originally posted by: edro
Who are you arguing with?

Isn't this common sense?

sometimes, some AT members, especially those that have been here a long time, just snap and become insane and start posting very strange stuff.

Spidey07 just needs some bedrest, preferably with a young redhead.

:Q

 

[FoBoT]

and the wii thread has a "digital is digital" reference at the moment, also talking about what cables to use with the wii

 

[DaveSimmons]

In practice have you ever had a toslink cable suffer only a partial failure for digital audio?

Even if so, was it anything other than obvious, i.e. sound cutting completely out or bursts of white noise intermittently?

Perhaps in the real world "it works or it doesn't" is a practical rule of thumb even if once in a lifetime there is a bad cable that only subtly degrades the sound quality.

 

[CraKaJaX]

that's why there's 1's, 0's, and then "tri-state mode"

 

[destrekor]

Originally posted by: UncleWai
There's no 4th dimension, God doesn't exist.

there are 10+ dimensions actually... the 4th is just the 'dot' that represents a point and the 5th is what connects two points in the 4th dimension, of which I still believe is known as the time dimension, although that may have changed with string theory.

 

[randay]

the plane doesnt take off
.999... is not equal to 1

 

[BrownTown]

If all you are saying is that the digital signals are infact represented by real valued voltages which can be affected in transmission than this is certainly not a big revelation to most here. The whole point though is that given a decent transmission line the distortion can be completely removed. So long as the noise in the distorted signal is not large enough to completely overshadow the actual data then a PERFECT transmission of data can be achieved. With an analog signal this is not possible because it is impossible to separate the noise from the actual signal. OF course you can try your best by modeling the channel be measuring the distortion in known signals and the like, be information is ALWAYS lost given a non trivial data stream.

 

[spidey07]

Originally posted by: BrownTown
If all you are saying is that the digital signals are infact represented by real valued voltages which can be affected in transmission than this is certainly not a big revelation to most here. The whole point though is that given a decent transmission line the distortion can be completely removed. So long as the noise in the distorted signal is not large enough to completely overshadow the actual data then a PERFECT transmission of data can be achieved. With an analog signal this is not possible because it is impossible to separate the noise from the actual signal. OF course you can try your best by modeling the channel be measuring the distortion in known signals and the like, be information is ALWAYS lost given a non trivial data stream.

I'm talking bandwidth and the rise/fall of the signal. Hence the aspect of time.

Some smart EEs can tell us about how this relates to the core size and intermodal dispersion within such a large core fiber and poor specs of TosLink transmitters and receivers.

I am not that EE however.

 

[Pheran]

Originally posted by: spidey07
You can't have an instantaneous state transition. There's this thing called time.

Especially with digital transmission. It's been a good 15 years since I've looked at the timing diagrams, but last I heard there are numerous encodings/framing/clocking/etc.

AFAIK, PCM audio has no error check. It isn't packetzed, but it is framed.

That is all. So let the smart EEs chime in.

In question is the very poor specs of TosLink. It's been a while since I looked at it but simple physics (core, wavelength) limit its bandwidth

It's certainly true that digital information is ultimately encoded and transmitted as an analog signal; the world is essentially analog after all (we'll ignore the ramifications of quantum physics for the moment ).

However, the question becomes, is the encoded signal within the tolerances of the receiver such that the receiver can derive a bitstream identical to what was sent from the source? If so, you just got a perfect digital copy and you can more or less ignore the transmission medium. If not, then errors were introduced and the limitations of the medium are impacting your signal.

Another different problem is time synchronization. This is not such a problem when you only have one signal, like a simple audio stream. But in home theater, you typically have video and audio signals that follow completely different paths through the system (as with Toslink audio and component video output) that may have different processing delays. This can lead to undesirable results such as a "lip sync" effect where the audio is no longer properly synchronized to the video, even though there are no actual errors in either data stream.

In any case, you'll get no argument from me that digital is not always perfect.

As a side note, I always get a good laugh whenever I see some company advertising "digital speakers".

 

[George P Burdell]

List of everyone who cares:

 

[destrekor]

Originally posted by: spidey07
You can't have an instantaneous state transition. There's this thing called time.

Especially with digital transmission. It's been a good 15 years since I've looked at the timing diagrams, but last I heard there are numerous encodings/framing/clocking/etc.

AFAIK, PCM audio has no error check. It isn't packetzed, but it is framed.

That is all. So let the smart EEs chime in.

In question is the very poor specs of TosLink. It's been a while since I looked at it but simple physics (core, wavelength) limit its bandwidth

-edit- thx for the correction sm8000.

but to continue the argument of the last thread, are you belief that digital coaxial is better than digital optical, or that HDMI presents a better digital medium versus digital optical? I know HDMI v1.3 can handle lossless audio for 7.1 with what, 30 audio streams? Can digital coax handle that same load? And can digital optical handle that load? I'd like to imagine so.

 

[silverpig]

Originally posted by: destrekor

Originally posted by: UncleWai
There's no 4th dimension, God doesn't exist.

there are 10+ dimensions actually... the 4th is just the 'dot' that represents a point and the 5th is what connects two points in the 4th dimension, of which I still believe is known as the time dimension, although that may have changed with string theory.

Pfft, no there ain't. We live in 3+1 dimensions.

 

[spidey07]

Originally posted by: destrekor
but to continue the argument of the last thread, are you belief that digital coaxial is better than digital optical, or that HDMI presents a better digital medium versus digital optical? I know HDMI v1.3 can handle lossless audio for 7.1 with what, 30 audio streams? Can digital coax handle that same load? And can digital optical handle that load? I'd like to imagine so.

I'm of the opinion that packetized audio does not suffer from jitter. Non packetized audio does.

But from a transmission medium perspective, coax greatly surpasses TosLink in terms of bandwidth. Just look at the specs of TosLink transmitters and receivers...that should tell it all.

 

[Hyperlite]

Originally posted by: Iron Woode

Originally posted by: edro
Who are you arguing with?

Isn't this common sense?

sometimes, some AT members, especially those that have been here a long time, just snap and become insane and start posting very strange stuff.

Spidey07 just needs some bedrest, preferably with a young redhead.

:Q

don't we all. :beer: