Chassis Ground layout for better ESD and EMI compliance

I think they fall out, but how is that an analogy?

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"Capacitive" stitching?

Not *too* concerned about that. I'm more worried about the huge current switching at 180MHz and its effect in the test chamber. ;-)

No. What powers the optocoupler? I really need an isolated 422 interface. Lots of them.

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Score one for Exxon-Mobil's lying propaganda. Joerg seems to live in a neighbourhood where no-one can read the scientific literature for themselves, or read critically enough to realise how nonsensical the Exxon-Mobil-inspired propaganda actually is. This comes close to saying that they haven't got enough minds between them for it to be worth trying to change them.

John Larkin's susceptibility to denialist propaganda is easy to explain - he doesn't even understand the basic facts about Darwinian evolution and DNA, and still thinks that because the weather is chaotic, climate has to be be too, which clearly indicates that he wasn't paying any attention in any of his science classes that weren't obviously relevant to electronics - but it seems a bit odd that an entire neighbourhood could be just as weak in science.

-- Bill Sloman, Nijmegen

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Except that you can't find any climate prediction that says California wasn't going to get lots of snow last winter.

You can find all sorts of idiot journalists saying that anthropogenic global warming has this or that implication for current weather, but actual climate predictions for the last few years and the next few years, by actual climate scientists, published in peer-reviewed journals are rather thinner on the ground.

The one example that comes to mind

actually predicted colder winters - in Europe - just before we had two cold winters in succession.

John Larkin doesn't read carefully enough to distinguish between idiot journalism and serious scholarship, and seems to think that the defects of the former debunk the latter. Not a particularly sensible - or insightful - attitude.

-- Bill Sloman, Nijmegen

Yup. Quote "Input-to-output ground plane stitching".

Wait until them thar flashin' shows up in them clouds and the computer gets all hairbrained :-)

But it take an incredible field-strength to upset these couplers.

I have mostly powered them via little transformers driven with a few

100kHz tapped off somewhere. Additional motivators were the requirements of 2nd source and low cost.

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Regards, Joerg

http://www.analogconsultants.com/

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All they have to do is count cords of wood.

John

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You really don't get it do you. The problem is not that the weather isn't conforming to your ideas of what anthropogenic global warming means for your local climate, but that you've never gone to the trouble of finding out what the climate experts actually have to say about the implications of anthropogenic global warming.

The kindest way of explaining this is that you lack the wit to realise that journalists wanting to make something of a local weather story will "explain" whatever it was in terms of anthropogenic global warming, when its just weather - as any climate scientist would have told them if they had gone to the trouble of asking. Sadly, that doesn't make for the kind alarmist story that journalists like to peddle to titivate the gullible public, of which you are a depressing example.

-- Bill Sloman, Nijmegen

...and they know what's happening all over the globe, eh?

Try counting cords of wood that used to be houses in Alabama, for a somewhat different metric. But, of course, that's not one tiny area of California, and one tiny area of California is, according to you, the entire globe.

All the rain/snow which has made the Mississippi exceedingly full also didn't fall in California, so it didn't happen on your "globe", either. Got it. Or your warped view is that global warming somehow means automatically drier, despite the fact that warm air carries more moisture from the ocean and dumps it in the mountains around you as more snow when it rises and cools. Or in Ohio to run down and flood Louisiana, as the case may be.

Nobody but Faux "News" thinks "a warmer climate" == "everywhere uniformly a little bit warmer" - in point of fact, "more chaotic" has been both predicted and observed - individual areas hotter, colder, wetter, drier, less predictable, more violent storms (see Alabama). Unseasonably hot April weather causing fruit trees to flower and be nailed by unseasonably late frosts are perfectly in line with "warmer on average" even though one involves a period of economically damaging cold. Two weeks of 30 degrees above average and two nights of 10 degrees below average will do that just fine, and still be "much warmer on average" - as will "your part of California having an Antarctic climate" and the rest of the country (or globe) being 1 degree (or less) warmer.

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Please don't feed the trolls. Killfile and ignore them so they will go away.

Is your problem radiated 300 MHz stuff, failing radiated EMI specs?

We use tons of these couplers, but we don't officially EMI test our VME modules, since they are just boards that go into racks.

We sometimes wave a spectrum analyzer around a board and see what's radiating. Things are getting scary. We buy some "programmable" crystal oscillators that have an internal PLL that runs at a couple of GHz, and they radiate a lot. The ADI couplers are indeed noisy. A 270 MHz ARM, or an FPGA with a 1 GHz serdes PLL, are probably bad; we'll be doing that combo soon, and I'll snoop it for fun.

We sometimes worry that such stuff will get into opamps and get rectified into noise and weird offsets, but haven't seen that as a problem so far. The RF seems very local to the chips, usually.

If you're failing EMI, you might try using the Silabs isolators. Or the TI parts. I think both have drop-ins for the ADUM parts.

John

Of course I have. I just think they have a decent probability of being wrong. Sciences not subject to experimental verification tend to get things wrong [1]. And they should avoid making specific predictions (as in our region headed for hot-and-dry) lest reality contradict.

But implications? They seem to be uniformly dismal. I can see how that would appeal to you.

John

[1] Superconductivity continues to confound the condensed-matter boys. See the latest Science mag.

John

Cite?

Google "climate change california drought" for lots of hilarious "emotive imagery", like...

Now you are confusing weather with climate.

John

Quote "As global warming melts the mountain snow that supplies fresh water to the densely populated Californian region ..."

ROFL! What are they smoking over there? But wait. East Anglia? Wasn't that where ...

[...]

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Regards, Joerg

http://www.analogconsultants.com/

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Exactly. The snow melts every year. There are no glaciers around here. We get a lot of our water from the melting snow. He says it like it's a bad thing for snow to melt.

What would be bad is if it didn't melt, namely we had another ice age and all the snow piled up, like it did 20K years ago.

72 feet of snow at Alpine Meadows this season. Maybe a little more to come; it snowed again last night. How's the weather at your place?

"Emotive imagery." Used to be called "science."

John

It peaks above 70F today. But only today, the weekend forecast is rain and cold. Somehow the 2011 summer will either be short or not happening :-(

Heating well into May we have now blown through five cords of wood this season, half a cord was scavenged from next year's supply so we may have to order extra. 10 years ago less than two cord sufficed.

A lot of this "science" sounds more like a ruse to press more taxes out of us. To feed some gravy train.

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Forgot to mention, we do have those. For example Mt.Shasta, and its glaciers are growing ...

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http://www.analogconsultants.com/

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I'm wondering the same thing. If it were my call, I'd connect the shield(s) to ground at the point that's closest to the hub of the star. Or maybe closest to the signal source. Or toss a coin. ;-P (I wonder if there's a rule of thumb?)

But I have no idea how that relates to shaking sticks out of a garden hose.

Cheers! Rich

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So where is the prediction?

The problem is that you haven't pointed to any such prediction, so it looks exactly as if you are wasting our time by being rude about an prediction that doesn't actually exist.

They don't. I'd be much happier if anthropogenic global warming just went away without us having to rebuild our energy economy, but since we do seem to be running out of oil and natural gas anyway, that particular cloud does have a silver lining.

Since investigating super-conductivity does involve experiments, I don't see what kind of point you think you are making here. And you seem to have missed the point that anthropogenic global warming involves more than just a rise in the earth's average temperature (which does happen to be going on at the moment) but also changes in the temperature gradients up through the atmosphere as well as a variety of other measurable changes.

You make a song and dance about Ca;ifornia weather not comforming to your ideas of what global warming theory predicts (not that you can be bothered to point us to any such prediction) but you can't be bothered to find out any of the other predictions it makes, even though some of them are going to be more easily detectable.

Anthropogenic global warming is a falsifiable hypothesis, despite the fact that you go around claiming that it isn't. If you put as much energy into finding some predictions it actually did make - rather than inventing predictions you would have liked it to have made - you might come over as something less of brain-washed propaganda victim.

-- Bill Sloman, Nijmegen

Around 10 years ago, the press here was full of official predictions that California was becoming hot and dry, because of AGW. Since then, it's been mostly cool and wet.

AGW people can always keep extending their time scales and still claiming they are right. Cute trick.

And there was Viner's (CRU) 2000 prediction:

within a few years winter snowfall will become ?a very rare and exciting event?. ?Children just aren?t going to know what snow is,? he said.

Yeah, right.

John

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It's actually what a reporter - Christopher Onions - wrote after talking to David Viner. They were talking about English winters, not Californian winters, and it looks as if Viner was extrapolating from what had been happening over the previous few years, which - in retrospect - looks more like a local warm period driven by the Atlantic Multi-Decadal Oscillation

As a prediction about California, it's a non-event. It was never published in a peer-reviewed journal and in fact sounds more like something created by selective quotation than any kind of formal prophecy.

You've also picked up Tim Lenton's comments about the increased likelyhood of drought in California. The clip doesn't mention any dates.

What he may have had in mind might be this

"Mean changes in the number of drought months relative to the 20th century baseline for 2036-2065 along the A1B (moderate emissions) scenario."

This is actually a prediction, but you are going to have to wait a few years before you can start claiming that current weather conditions falsify it.

Bottom line is that you have set up a straw man and you don't know enough about what you are talking about to realise it.

-- Bill Sloman, Nijmegen