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Difference between digital and coaxial socket?

fegs said:
is it not binary?
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Of course it is. The voltage of an S/PDIF signals alternates between positive and negative. At the start of each bit interval there is a transition. For 1 bits, there is a second transition at the halfway point. For 0 bits, the polarity remains unchanged throughout. Thus, the polarity in the second half of the bit interval is either the same or different from that of the first half. In other words, it's binary. The rise and fall times have to be less than 20% of one bit time.
 
fegs said:
Surely if it’s digital it’s just a series of 1’s and 0’s anyway, I’d have thought providing the cable is fit for purpose that’s enough?
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If you look into it you'll find it's not that simple. There are known reasons why SPDIF cables don't sound the same, it's quite interesting.
 
fegs said:
cheers thanks, always happy to be educated
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It's worth mentioning that my preferred cheapo cable is not as good as the others I tried in Hi-Fi terms. What I mean is that other cables provided more detail but sounded more 'digital', if you like? It wasn't a very big difference but the 'better' cables had a glassy top end that made you want to stop listening. The cheap cable just sounds that little bit smoother and more together.

I certainly can't imagine how a coax cable costing, say a grand, could justify itself based on what I've heard between a £200 cable and a £2 one.
 
Cav said:
For optical or digital coax I use cheap stuff from ebay or Amazon.
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Again, it's worth looking into. Most people assume that digital systems work in broadly similar ways, but they don't. For example, there are technical reasons why two coax cables might sound different but HDMI either works perfectly or it's broken.
 
Mr Pig said:
Again, it's worth looking into. Most people assume that digital systems work in broadly similar ways, but they don't. For example, there are technical reasons why two coax cables might sound different but HDMI either works perfectly or it's broken.
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I have never heard any difference in optical or digital coax nor would I expect to however expensive it was.
 
Three common "confusing the container with the contained" assumptions seem to be muddying the water here.

1) 'Coaxial' is a physical description of the arrangement of the conducters. The term has nothing to do with making the cable 'analogue' or 'digital'.

2) Similarly, regarding the way the signal voltage pattern varies as 'analog' or 'digital' is a matter of how the information being being conveyed is represented by the way the voltage varies with time.

3) A serial digital signal pattern does not *have* to have 'flat tops' or 'instantaenous transitions'. It just needs to be shaped sufficiently well that the reciever can work out reliably which sections are flagging a '1' and which are flagging a '0'.
 
mansr said:
Oh, really? You should write to the IEEE and let them know.
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I don't know who that is but if they know their stuff they already will.

Jim Audiomisc said:
1) 'Coaxial' is a physical description of the arrangement of the conductors. The term has nothing to do with making the cable 'analogue' or 'digital'.

2) Similarly, regarding the way the signal voltage pattern varies as 'analog' or 'digital' is a matter of how the information being being conveyed is represented by the way the voltage varies with time.

3) A serial digital signal pattern does not *have* to have 'flat tops' or 'instantaneous transitions'. It just needs to be shaped sufficiently well that the receiver can work out reliably which sections are flagging a '1' and which are flagging a '0'.
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Yeah yeah, we know, but in the context of the conversation we know that coax is being used to identify one kind of digital connection from another. While it is true that the transitions do not have to be instantaneous, which in practice they can't be anyway, if the transition is too long or out of place it can be misread. And it doesn't matter how the voltage pastern varies, the signal sent along the cable is analog, only converted to a digital signal by processing at the other end.
 
We desperately need one of those fake news flagging systems here on pfm as there exists a cabal of certain people who in spite of having feck all knowledge of electronics cannot help but give an opinion on almost every technical matter and are completely, spectacularly and laughably wrong 99.999% of the time. In fact these repeat offenders very often post stuff that is so silly it is not even possible under the laws of physics. Sadly when a question is asked by an OP and is definitively answered by an engineer or physicist or three there will almost always then be a slew of counter "opinion" from people who don't know a resistor from a radish, sometimes resulting in the OP posting on the lines of "oh there seems to be a huge range of opinions here, some very contradictory, I hadn't realised this was such a complicated and divisive matter and feel more confused now than when I started out".... NO! They were often given the correct answer by two or three people who know what they're talking about on the first page and then 12 people who really haven't got a clue have talked complete bovine arse gravy for the next 4 pages!
Strangely enough when the technical content goes beyond a piece of wire they often (but not always) go ominously quiet... odd that although they seem completely clueless on the simplest things such as an emitter follower, and no doubt think a cascode is something like a barcode..... and that transformers was a great kids toy.. when we get to the most simple of all, like a meter of mains cable or a fuse, they become "world renowned experts" who regard themselves in possession of such profound wisdom as to be able to pooh pooh the professional opinion of electronic engineers and physics professors. Strange days indeed....

Ah that's better:):rolleyes:


Carry ono_O
 
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