I had to google UTP..
A shielded cable is only one possible config. With twisted pair, one is still forming the ground loop. While the purpose of the grounded conductor is to pass along the zero point reference, it forms a loop and carries inducted currents.
Any grounding conductor on an IC is trying to cancel the induced voltage caused by a loop. The lower the grounding loop, the higher the current and therefore the better the cancellation.
Others will be more well versed in farfield rf induction, I've only discussed near field magfield.
Cheers, John
I wonder what's the best way to measure this ? A magnetic field/gauss meter, a multimeter across a loop antenna ?
Gen-El Gauss Master
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In that case I can only hope that Thorsten's right when claiming that solid conductors ar good when transfering low and midrange signals whilst the shileld/bride is superior when it comes to high frequencies or extremes as he calls those. (see UBYTE-2 article)
For those interested I can add a couple of links with a "slightly" different approach namely braiding:
Cat5 and Josef Svalanders version. The latter is written in swedish but you guys are smart so quick learning swedish shouldn't be a problem for you
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Sorry, more nonsence. He`s primarely right about overpriced mumbo-jumbo cables, but he`s wrong when he claims there`s close to no difference aso.
RF EMC and cables, when EMC testing the bigest problem is the fact that every cable is an antenna!
Design Techniques for EMC: cables and connectors
RA EMC Awareness - Mitigation - shielding cables
Design Techniques for EMC: cables and connectors
RA EMC Awareness - Mitigation - shielding cables
Can we, for the sake of discussion, consider HDMI cables as "interlinks"?
Just watched a national program called "Radar" which is a consumer-test type program on public TV here in Netherlands.
They tested 5 HDMI cables. Price range: 2.99 euro to 139.99 euro.
Cables were connected to 5 identical displays, carefully adjusted for identical color and hue etc.
There were three testers:
- a 'colorist' and filmmaker who, professionally, is used to judging colors, resolution etc. This tester didn't know which was which, single blind test;
- a 'technician' who connected the cables and commented on the gold plating (all but one), the 'fit' and mechanical properties of connectors and cables and such. He knew what was what, a sighted test;
- a professional film critic, single blind test;
The test material was a colorfull cartoon.
Results:
The colorist couldn't see any difference;
The technician selected the most expensive cable because the thicker cable 'felt reliable', although he mentioned that care should be taken not to sharply bend the thicker cable;
The film critic clearly saw differences between one cable and the 4 others: the one had at the same time sharp boundaries between different colors yet those differences were not 'harsh'.
The cable he singled out for best quality was the 2.99 one.
Conclusions?
jan didden
Just watched a national program called "Radar" which is a consumer-test type program on public TV here in Netherlands.
They tested 5 HDMI cables. Price range: 2.99 euro to 139.99 euro.
Cables were connected to 5 identical displays, carefully adjusted for identical color and hue etc.
There were three testers:
- a 'colorist' and filmmaker who, professionally, is used to judging colors, resolution etc. This tester didn't know which was which, single blind test;
- a 'technician' who connected the cables and commented on the gold plating (all but one), the 'fit' and mechanical properties of connectors and cables and such. He knew what was what, a sighted test;
- a professional film critic, single blind test;
The test material was a colorfull cartoon.
Results:
The colorist couldn't see any difference;
The technician selected the most expensive cable because the thicker cable 'felt reliable', although he mentioned that care should be taken not to sharply bend the thicker cable;
The film critic clearly saw differences between one cable and the 4 others: the one had at the same time sharp boundaries between different colors yet those differences were not 'harsh'.
The cable he singled out for best quality was the 2.99 one.
Conclusions?
jan didden
why do pop comparisons never know the tech well enough for valid "debunking"
there really are no "identical displays" at close enough visual comparison - manufacturing variations can be quite visible in serial production/same model
the only way to have significant results involve switching the cables to the exact same display
of course no competent digital interface should have any problem with the cable until bits start getting corrupted
there really are no "identical displays" at close enough visual comparison - manufacturing variations can be quite visible in serial production/same model
the only way to have significant results involve switching the cables to the exact same display
of course no competent digital interface should have any problem with the cable until bits start getting corrupted
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So the critic did see a difference on a cartoon! Not the subtle shadings often mentioned as being the difference.
They picked the cheap cable as the best, so how do they do in recommending films?
I presume the different cable was the one without gold plated connectors. That does make a measurable difference.
displays have to be adjusted not only by static patterns, but also dynamic patterns as well. I doubt they did all the adjustment tests necessary.
I would think that Cartoons are among the worse sources to compare with since you have no daily impression of what is being displayed.
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No the non-plated connector cable was euro 49.95 IIRC.
The 139.95 one was a Monster cable, by the way.
jan
displays have to be adjusted not only by static patterns, but also dynamic patterns as well. I doubt they did all the adjustment tests necessary.
I would think that Cartoons are among the worse sources to compare with since you have no daily impression of what is being displayed.
Well, they showed the 5 displays next to each other. The testers just walked from one to the other and back several times. Sort of instantaneous comparison.
Your logic for the adjustments is incorrect I'm afraid; if they cannot see any differences between the displays, they either are perfectly identically adjusted, or the mis-adjustment is so small that it doesn't lead to a difference in perception.
jan didden
I think the comparison is not as ideal as it can be. If the displays do not meet certain specifications, no matter how you match them, they are just going to mask differences created upstream. So we have different opinions. No big deal for me.
Sure, but if I look at 5 displays, each fed by a different cable, and they all look identical to me, doesn't that mean by definition that the cable doesn't matter? For THESE displays, sure. They were supposed to be high-end displays, don't remember the type or brand.
jan
Well, sure. But I can tell you that it's not likely to be missed on HD. I make my living running video cables - bad ones you can see, no problem. Long runs with limited bandwidth you can see, too. Same with bad connectors.
Video is finicky.
But Jan's answer is best.
True, if the goal is to see if the cable differences matter for those specific displays. But that cannot conclude in general whether cables matter or not. I've looked at many displays, and there are really only a handful that I would prefer regardless of price. Back in the early years of LCD TVs, I went though a whole show, and only one particular model stood out. Purchased it, and only recently spent the time to adjust it to it's full potential after I decided that HD programs were popular enough to subscribe to such.
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