First post so please excuse my ignorance....
I’v been pondering over this question for a while. I have a telecoms background and know a few things about digital cabling in general, although I’ve no knowledge of error correction/bit error rates, line speed negotiation, clocking etc.. with for example USB1.1/2/3 or SPdif/toslink etc.type interfaces.
If the digital interface specification is exceeding the required line rate (in relation to the sample rate of the material) and the interlink is conform specification then what difference does the “perceived” quality of the cable make? Since all we are trying to achieve is to recover sufficient bits at the other end.
The only thing I can think of is that these interfaces are prone to produce a lot of bit errors if no quality components are used. Is there a way (possibly some software), to measure this with.
I’v been pondering over this question for a while. I have a telecoms background and know a few things about digital cabling in general, although I’ve no knowledge of error correction/bit error rates, line speed negotiation, clocking etc.. with for example USB1.1/2/3 or SPdif/toslink etc.type interfaces.
If the digital interface specification is exceeding the required line rate (in relation to the sample rate of the material) and the interlink is conform specification then what difference does the “perceived” quality of the cable make? Since all we are trying to achieve is to recover sufficient bits at the other end.
The only thing I can think of is that these interfaces are prone to produce a lot of bit errors if no quality components are used. Is there a way (possibly some software), to measure this with.
Digital signaling is effective HF signaling.
The cable and it's connectors must be suitable for HF.
That means accurate terminations at both ends and accurate maintenance of the cable impedance through the connectors and of and onto the boards.
If it is specified for 75ohm, then everything must be 75ohms +- some tolerance.
RCAs don't work !!!!
The cable and it's connectors must be suitable for HF.
That means accurate terminations at both ends and accurate maintenance of the cable impedance through the connectors and of and onto the boards.
If it is specified for 75ohm, then everything must be 75ohms +- some tolerance.
RCAs don't work !!!!
It can be if the cable is assembled from, for example, gold plated solid core silver hot conductor while the insulation material/dimensions and shield construction still provide 75 ohms impedance. Termination is crucial; fine tuning is expensive. But the end results can be quite outstanding. Yes, I know – it is only a stream of 0’s and 1’s…
Boky
If the cable is correctly engineered, then no difference. It is basic digital signal transmission of which there is plenty of information out there. The main thing as already pointed out is impedance matching, get that correct and avoid impedance mismatches then you will have no problem
Exotic materials, gold or silver connectors are not gonna make any difference, but this is audio so like everything else there are myths regarding digital cables and digital signal transmission.
The basic method of looking at an interface is to use eye diagrams, this gives you the overall picture of how well the cabling and interface is performing.
Exotic materials, gold or silver connectors are not gonna make any difference, but this is audio so like everything else there are myths regarding digital cables and digital signal transmission.
The basic method of looking at an interface is to use eye diagrams, this gives you the overall picture of how well the cabling and interface is performing.
Sure about that? What about the speed the signal travels down the wire? Can you check that as well by observing the eye-pattern in a single instance in time? Saying that this speed is not important is the same as implying that jitter doesn't make any difference with regard to digital sound. And how about the oxidation and the resulting loss due to the increased resistance and the skin effect at high S/PDIF frequencies? Do you know that even silver - oxide is a better conductor compared to copper? All this aside -> have you ever heard what gold-plated pure silver, annealed cable does to the (even digital S/PDIF) sound?
It is possible to extrude the {RCA pins at both ends WITH the "hot" solid core wire between them RCA pins}, from a single piece of the thick silver wire. No soldering required.
It is possible to extrude the {RCA pins at both ends WITH the "hot" solid core wire between them RCA pins}, from a single piece of the thick silver wire. No soldering required.
Hi,sorry but yes I’m sure and yes you can observe the speed a signal travels down a wire, ie with what modulation and frequency using the eye pattern method, and observe how cleanly it does so. Jitter only becomes a problem in a digital signal path once the bits can no longer be recovered at the opposite end, but within cable/interface specification this is no problem. In a digital context, BER (Bit error rate) is a much more relevant metric.
What a load of rubbish, gold or silver conductors will not make any difference to digital signal transmission. S/PDIF is that fast, providing the correct driver IC's are used, ie ones without silly rise times.
Skin effect and signal speed problems aint ever gonna be a problem again at the speed S?PDIF runs at, and skin effect in cables is not to much of a problem, on PCB traces where you have rectangular shaped conductors a ground plane localy etc then you may get some problems in the higher frequency stuff, but not what your average Audio DIYer is gonna ever see.;
Eye diagrams take jitter into account, you use them to get an overall view of the signal transmission.
How fast does a digital signal travel down a cable, and what causes the speed to be below that of light? The metal the conductor is made of has nothing to do with it what so ever. Speed for SPDIF signals isn't again going to be a problem, they are just to slow.
Basically you are just sprouting Audiophile digital myths and hand waving as I believe the expression is, go read Dr Eric Bogatin, Dr Howard Johnson, Ralph Morrison etc then you may get some understanding of digital signal transmission. Oh and electrons in any conducting metal only travel at about 0.1mm per second if that.
So for digital signals silver wire will not make the signal travel faster or provide any real benefits, MYTH...
Skin effect and signal speed problems aint ever gonna be a problem again at the speed S?PDIF runs at, and skin effect in cables is not to much of a problem, on PCB traces where you have rectangular shaped conductors a ground plane localy etc then you may get some problems in the higher frequency stuff, but not what your average Audio DIYer is gonna ever see.;
Eye diagrams take jitter into account, you use them to get an overall view of the signal transmission.
How fast does a digital signal travel down a cable, and what causes the speed to be below that of light? The metal the conductor is made of has nothing to do with it what so ever. Speed for SPDIF signals isn't again going to be a problem, they are just to slow.
Basically you are just sprouting Audiophile digital myths and hand waving as I believe the expression is, go read Dr Eric Bogatin, Dr Howard Johnson, Ralph Morrison etc then you may get some understanding of digital signal transmission. Oh and electrons in any conducting metal only travel at about 0.1mm per second if that.
So for digital signals silver wire will not make the signal travel faster or provide any real benefits, MYTH...
Hi,
does the cable behave like a transmissioline anyway?
Freqs as high as 25MHz mean 10-12m wavelength.
And even 1/2 or 1/4 of that is longer than the typical interconnect.
The cable should then behave like a lumped impedance.
But of course silver or gold makes an even bigger difference, if the digital signal is also buffered in memories and reclocked. Ohhh yessss
jauu
Calvin
does the cable behave like a transmissioline anyway?
Freqs as high as 25MHz mean 10-12m wavelength.
And even 1/2 or 1/4 of that is longer than the typical interconnect.
The cable should then behave like a lumped impedance.
But of course silver or gold makes an even bigger difference, if the digital signal is also buffered in memories and reclocked. Ohhh yessss
jauu
Calvin
What's of interest here is the rise / fall time of the signal. If you know that you know the highest frequency of interest (can be much higher than 25MHz).
The rest is just basic transmission line theory... As pointed out here already, try googling "signal integrity" for more info on the subject.
The rest is just basic transmission line theory... As pointed out here already, try googling "signal integrity" for more info on the subject.
It is the signal rise time that determines whether a signal is high speed, whether the cable should be treated as a transmission line, and when and where the reflections if any will arrive back at the driver.
If your drive strength, Tr (rise time of the signal) and impedances are all matched you shouldn't get any reflections...At the end of the day reflections are caused by too much energy being fed into the line, for whatever reasons, that cane be absorbed by the far end. Impedance mismatches down a line will also cause reflections.
But as said with a reasonable cable with SPDIF you should have no problems, sub nano second rise times will also help.
Without high speed simulation software to determine what is going on and modelling the cable and all the interfaces, you can only approximate what is happening (you need the IBIS data for the transmitter and receiver devices as well).
If your drive strength, Tr (rise time of the signal) and impedances are all matched you shouldn't get any reflections...At the end of the day reflections are caused by too much energy being fed into the line, for whatever reasons, that cane be absorbed by the far end. Impedance mismatches down a line will also cause reflections.
But as said with a reasonable cable with SPDIF you should have no problems, sub nano second rise times will also help.
Without high speed simulation software to determine what is going on and modelling the cable and all the interfaces, you can only approximate what is happening (you need the IBIS data for the transmitter and receiver devices as well).
As Mark as pointed out and I have mentioned the rise time (and fall time) are the determining factors for spectral content of digital signals, look up Knee frequency:
Fknee=1/Squ Rt Tr
1 over the square root of the rise time.....
Again though without SIV software and 3D field solvers etc you can only approximate or guess.
And just in case, using silver as the conductor does not make the signal travel faster than it does in a copper conductor, which I believe was what was being hinted at with the mention of silver conductors.
Some notes on skin effect (and ground effect) just to add a bit of icing to the discussion...
http://www.ultracad.com/articles/skin effect.pdf
Fknee=1/Squ Rt Tr
1 over the square root of the rise time.....
Again though without SIV software and 3D field solvers etc you can only approximate or guess.
And just in case, using silver as the conductor does not make the signal travel faster than it does in a copper conductor, which I believe was what was being hinted at with the mention of silver conductors.
Some notes on skin effect (and ground effect) just to add a bit of icing to the discussion...
http://www.ultracad.com/articles/skin effect.pdf
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