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HDMI cables

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So how was the light meant to propagate through gold again?

With science!

 

Those were atoms, not photons.

 

Well if you want to get all technical, they were bosons. Clearly, however, gold is inherently permeable. Is it really so hard to believe that light could find a way through? :-P

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So how was the light meant to propagate through gold again?

With science!

 

Those were atoms, not photons.

 

 

Redhatter lays down the smack down again!

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As i've written several times. Digital is a lot more 'simple' than analogue, in that the data consists of 0 or 1, no 'frequencies' etc. And a slong as the signal reaches the other end, its fine. even if it drops a bit of data, most things can 'guess' what it was and you often wont even see.

That's a complete load of nonsense. Fourier would be spinning in his grave reading that!

 

The only signal that has "no frequencies" is flat plain DC with absolutely all noise filtered out. Everything else, has a frequency, and anything more complex than a theoretical sine wave will have a bandwidth. Ergo, all signals have a bandwidth.

 

In the case of the "digital signal" you described earlier… it's a whole heap of these concatenated together, correct?

 

Posted Image

 

That, dear viewers, is the Gate function or Rectangular function. It's comprised of two Heaviside step functions subtracted from each-other, one delayed relative to the other. The width (in seconds) is the reciprocal of the frequency (in Hz). So a repeating signal where each one of those pulses is 500µs wide, spaced apart 500µs (thus: 1ms period) equates to a 1kHz square wave.

 

Take the Fourier transform of that, or set up an oscillator and throw the resulting signal at a spectrum analyser, and you'll see this:

 

Posted Image

 

Ohh look at that, not just one frequency, there are thousands of them. Lots of juicy harmonics too. In fact, it's for this reason that high-speed signals are never sent this way. The pulses are shaped to more closely resemble sine waves.

 

Raised Cosine filters are one such example of this. GSM mobile phones use Gaussian Frequency Shift Keying, if you were to "tune in" on the FM carrier generated by one of these, you'd see the pulses have a Gaussian shape to them. There are numerous of others too, some use a truncated/delayed version of the normalised sinc function shown above.

 

Yes, you're right that it's digital, but all signals with any interesting content occupy frequencies and bandwidth. And no, it's not more simple than analogue, it's just easier to filter noise out than with analogue.

 

I think what he is trying to say is that digital coms can sustain lower SNR because a correlator like a matched filter can still recover symbols with a very high success rate even in the presence of high amplitude AWGN or phase shifting or w/e while any channel transform applied in the transmission of an analogue signal is preserved and will affect picture quality.

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I'd be interesting to hear the salesperson's justification for the $50 additional cost.

Awesome technobabble

 

Holy hell. I think I've come one step closer to understanding how a regular average joe feels when they watch an episode of Star Trek: TNG. I'd love to connect up to a mesh network, but I have a long way to go in learning the ropes. (At least, that's what I'm assuming this is all about).

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I'd be interesting to hear the salesperson's justification for the $50 additional cost.

Awesome technobabble

 

Holy hell. I think I've come one step closer to understanding how a regular average joe feels when they watch an episode of Star Trek: TNG. I'd love to connect up to a mesh network, but I have a long way to go in learning the ropes. (At least, that's what I'm assuming this is all about).

 

Meh, id personaly buy a cable that has;

gold plated plugs (simply to survive the test of time), Nice solid cables.

 

If your after long cables. Go for the *slightly* dearer cables. If your after a simple meter length go for a cheap ass one. (I got mine from coles, 10 bucks. Gold plated, braided cables)

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Even the RITMO $5 cables at MSY are gold plated. Spending money on digital above and beyond 'it works' is a waste of money.

True that.

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Meh, id personaly buy a cable that has;

gold plated plugs (simply to survive the test of time), Nice solid cables.

I'm not even convinced the gold plating helps with that. With frequent use, the gold plating is the first thing to rub off, as it's usually only nanometers thick.

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Meh, id personaly buy a cable that has;

gold plated plugs (simply to survive the test of time), Nice solid cables.

I'm not even convinced the gold plating helps with that. With frequent use, the gold plating is the first thing to rub off, as it's usually only nanometers thick.

 

 

Yep and the only thing I can see gold plating could possibly help with is corrosion on hdmi adaptor. But as redhatter said it comes off pretty easy.

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That's too much thought for me before beer.

I simply assumed gold plating was used as a contact surface as it was a brilliant electricity conductor.

Never considered anti corrosion properties. And I live in a unit prone to mould, rust and general corrosion. You'd think I would have thought about this earlier.

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Meh, id personaly buy a cable that has;

gold plated plugs (simply to survive the test of time), Nice solid cables.

I'm not even convinced the gold plating helps with that. With frequent use, the gold plating is the first thing to rub off, as it's usually only nanometers thick.

 

 

Yep and the only thing I can see gold plating could possibly help with is corrosion on hdmi adaptor. But as redhatter said it comes off pretty easy.

Its better then not having it. Gold has a tendency to *not* corrode, yes. Granted it doesn't help a digital in any way, but, If you can get gold plating for 10 bucks why in the hell not?

At the end of the day all your unused cables could be salvaged for the gold in em, Wooo. Ok probably not, but still.

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Hmm, let's compare resistivity of some common connector plating metals:

 

  • Silver: 15.9nΩ.m with coefficient 0.0038 1/K
  • Copper: 16.8nΩ.m with coefficient 0.0039 1/K
  • Gold: 24.4nΩ.m with coefficient 0.0034 1/K
  • Nickel: 69.9nΩ.m with coefficient 0.0060 1/K

What's the difference? Not a lot even for a metre long wire of the stuff, you'll have more impedance in the surface-to-surface interface than in the contact plating. 8nΩ is less than most electronics can detect. Anti-corrosion properties are probably the only factor I can think of as being a desirable feature.

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So, its a feature none the less. May aswell get a gold plated one like I said if your only gonna pay 10 bucks.

 

It's like going down the road for some milk. You get to the shop and pick yourself up a 2ltr and pay for it. The dude at the counter sticks it in one of those flimsy blue spastic bags and you think to yourself "Hrm.. I have to walk home... This bloody bag is going to break!" but then you think "Bah, doesnt matter I only live a block away. She'll be right!" You pause for a moment and then ask for a double bag job anyway. After all, its free so why not?

 

Now, you could have gone with the single bag. But there is potential for it to bust and you loose your milk all over the road. Shattering your dream for a nice cuppa tea. Sure, you have made the trip plenty of times. Haven't lost one yet! But this could be the day...

But instead you went with two bags. And you now trot home paying no mind to your precious cargo.

 

The odds of corrosion much like the loss of milk is unlikely. But, a bit of peice of mind for nothing? Why not?

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eeeeeeeeerrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr

rrrr.

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a 'gold plated connector' is 90% of the time only gold plated on the outside 'ground' section. the pins themselves are still copper. its a gimmic

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Didn't know that, so just the outer shell of the connector? not the pins themselves? what in fucks name is the point in that?

Ok, disregard what I said. Seem's like more gold is used for the outer shell of the connector then would have been used on just the pins. Doesn't make any sence.

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So, its a feature none the less. May aswell get a gold plated one like I said if your only gonna pay 10 bucks.

 

It's like going down the road for some milk. You get to the shop and pick yourself up a 2ltr and pay for it. The dude at the counter sticks it in one of those flimsy blue spastic bags and you think to yourself "Hrm.. I have to walk home... This bloody bag is going to break!" but then you think "Bah, doesnt matter I only live a block away. She'll be right!" You pause for a moment and then ask for a double bag job anyway. After all, its free so why not?

 

Now, you could have gone with the single bag. But there is potential for it to bust and you loose your milk all over the road. Shattering your dream for a nice cuppa tea. Sure, you have made the trip plenty of times. Haven't lost one yet! But this could be the day...

But instead you went with two bags. And you now trot home paying no mind to your precious cargo.

 

The odds of corrosion much like the loss of milk is unlikely. But, a bit of peice of mind for nothing? Why not?

Well, normally the milkman delivers the milk here, but if I have to get it myself, I only have to carry it from the counter to the basket on the bicycle, so I don't even bother with a bag, save the plastic for something more worthy. Just like the gold plating (on the outside) of connectors, it's a pointless exercise.

 

No use crying over spilt milk.

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Just like the gold plating (on the outside) of connectors, it's a pointless exercise.

Bbbbbbbbut it's shiny!!!!!!!!!!!!!!!!!!!!!!!

 

:P

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and THATS our point.

 

afaik, copper is a better conductor than gold anyway, gold is just more resistant to oxidising\corrosion.

 

Correct me if i'm wrong, i'm a little busy to google specifics.

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Electricity only passes over the outside of a wire anyway so gold plating does increase conductivity. Silver is supposedly a better conductor then gold or copper but because both silver and copper oxidize they form corrosion and that increases resistance - gold however does not, so in low voltage or any application where low resistance is necessary it is the superior metal. Especially with unsoldered joins like hi fi terminals.

 

of course whether or not this increases audio/video quality over say stainless steel is another matter.

Edited by UberPenguin

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There's also the marketing train of thought where gold is softer, ergo makes a "better contact" because the contacts can smoosh together better.

 

Yeah. I've been told this by a salesperson before. *rolls eyes*

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Electricity only passes over the outside of a wire anyway so gold plating does increase conductivity. Silver is supposedly a better conductor then gold or copper but because both silver and copper oxidize they form corrosion and that increases resistance - gold however does not, so in low voltage or any application where low resistance is necessary it is the superior metal. Especially with unsoldered joins like hi fi terminals.

 

of course whether or not this increases audio/video quality over say stainless steel is another matter.

  • Silver: 15.9nΩ.m with coefficient 0.0038 1/K
  • Copper: 16.8nΩ.m with coefficient 0.0039 1/K
  • Gold: 24.4nΩ.m with coefficient 0.0034 1/K
  • Nickel: 69.9nΩ.m with coefficient 0.0060 1/K

If that is the intent, then they should be copper-plating the gold, not gold-plating the copper. Insertions and removals will erode the corrosion as well as any gold plating. As for skin effect, it'll be passing through the copper only, the oxidation will be an impediment when passing from one conductor to the next. It'll have a small, but minimal effect on the resistance through the conductor as it effectively reduces the outer diameter (and by extension, the surface area). The dissimilar metals will probably make the situation worse though, as it can set up something like a P-N junction, weakly rectifying the current.

 

I've heard of this happening in trap dipole antennas, creating lots of harmonics of the fundamental frequency, much to the owner's dismay. Worse is when some water gets into the traps, causing an electrolytic effect in the trap. It's a trap for young players.

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