Talk:Electromagnetic compatibility

Suggestions

all three last links are broken / target is missing.

Would like to add the following:

0. EMI Generator/Medium/Receptor model

1. EMI Regulation

1.A That emissions limits set by regulatory bodies like the FCC involved protecting radio services across the electromagnetic spectrum. Many of the limits for Information Technology Equipment once related to the electric field noise voltage thresholds of normal household TV and AM receivers, and the annoyance factor when offending emissions exceeded these threshholds. Despite the proliferation of non-"radio wave" delivery media, e.g., satellite, cable, the Internet, file-sharing networks, etc., some of these traditional limits still exist. For example, so many of the lower-frequency emissions measurements are made using "quasi-peak" detection, with filters that roughly correlate the annoyance factor that culprit emissions would have to the enjoyment of an AM radio station. Average, peak, and Root Mean Square (RMS) detection is also used for electrical voltages, currents, electric fields, magnetic fields.

2. EMI impact in these industry and product groups:

2.A EMI in these categories: industrial electric power distribution equipment and switching stations, heavy industrial machinery and equipment, RF and wireless devices, Information Technology Equipment (ITE), Telecommunications Terminal Equipment, Industrial, Scientific, and Medical (ISM) equipment, tools, lighting equipment, engines and motors, household appliances, etc.

3. EMI Sources

3.A Sources of unintentional EMI, besides clocks.

3.A.1 Although digital clocks are a primary source of unintentional EM emissions, there are also the following COUPLING sources:

3.A.1.a Transmission lines, cables, and antennas

3.A.1.b Ground, earthing/grounding, and bonding

3.A.2 There are non-clock switching in these systems and devices: electric power distribution substations; communications and telecommunications; industrial process control; mechanical and electromechanical; switches; relays;

3.A.3 Non-clock, non-synchronous, non-switching, and incoherent, spurious sources:

3.A.4 Wideband arc/corona effect of high voltage power distribution transmission lines or devices: transformers; insulators; switches; relays; spark generators, e.g., arc welders, autos; noise;

3.A.5 Natural phenomena sources: sun spot activity, solar wind and the ensuing "aurora borealis," or "Northern Lights;" lightning strikes,

3.A.6 Single-shot or bursty transient effect EMI sources

3.A.6.a Electromagnetic Pulse (EMP) Nuclear Electromagnetic Pulse (NEMP), HEMP (High-altitude Electromagnetic Pulse) from nuclear bombs.

3.A.6.b Electrostatic Discharge (ESD)

3.B Intentional EMI sources:

3.B.1 Radio communications services and transmitters intended for emission in other frequency spectra;

3.B.2 Jamming and Electromagnetic Pulse (EMP)

4. EMI History Section

The research and development of EMI as weaponry also has a rich history in advanced militaries. For example, the effects of Electromagnetic Pulse (EMP) has long been studied. Large-amplitude EMP is a byproduct of detonation of atomic and nuclear bombs. Large vessels and aircraft have the ability to confound enemy communications systems with intentional EMP. The 1991 Iraqi war saw among one of its first strategies the use of aircraft in blanketing of Iraq communications infrastructure with very effective intentional interference. Though not really "jamming," in WWII the US and British dropped half-wavelength aluminum strips ("chaff") to confound Axis radar systems, producting false echos, in a form of electromagnetic obfuscation and cover for friendly aircraft.

DonL 07:13, 2 December 2006 (UTC)[reply]

Apology

I recently found out that removing another's text is not a "minor" edit. Sorry -- I may have violated that in this site.

DonL 05:44, 10 December 2006 (UTC)[reply]

Spelling

In diagram: "sinc" should be "sink" --Aulis Eskola (talk) 17:20, 25 March 2008 (UTC)[reply]

Yes. However, in EMC, I think the terms "source and victim" are more common than "source and sink". --68.0.124.33 (talk) 15:47, 10 July 2008 (UTC)[reply]

"Victim" is more suitable, yes. -- Cheers, Steelpillow (Talk) 19:53, 10 July 2008 (UTC)[reply]

Victim may be the industry word, but imho to the casual reader it has an inflationary effect and dramatic connotation which pays a disservice to understanding the science. Suggest evaluating that terminology for the good of wiki. 107.142.107.47 (talk) 04:24, 7 September 2017 (UTC)[reply]

ISM bands

Currently the article claims "Where high emission levels were a potential problem (such as microwave ovens), equipment manufacturers could usually avoid emissions limits through the choice of certain unlimited Industrial, Scientific and Medical (ISM) frequency bands", which I think gets it exactly backwards.

My understanding is that microwave ovens were popular long before there was such a thing as the ISM band. After microwave ovens became popular, Audio and TV broadcasters (commercial, amateur, military, etc.) did not want the "microwave oven" frequencies, because they didn't want their broadcasts disturbed by the occasional faulty microwave oven. Later, when manufacturers wanted to sell transmitters to everyone, even people not licensed to transmit, and requested an unlicensed band, they were given the band that none of the licensed broadcasters wanted. (This is a bit of "popular oral history"; I suspect the true story is a little more complex. How did microwave oven manufacturers pick the frequencies they use?).

Certainly the "unlicensed" bands have much more relaxed limits than the strict limits in the "licensed" bands. However, my understanding is that they still do have some limits -- they are not "unlimited". --68.0.124.33 (talk) 14:40, 8 July 2008 (UTC)[reply]

AIUI, the microwave oven and other ISM frequencies were chosen by manufacturers before the modern regulatory framework was in place. When the regulators drew up their rules, most of them were aimed at preventing interference within the newly "licensed" bands. The ISM bands were created because existing ISM users could not just be turned off, and it was too late to use the bands for anything else. Last time I looked (admittedly many years ago), emissions within the ISM bands were only limited by other regulations, such as health & safety. But woe betide the ISM emitter who accidentally broadcast harmonics outside the ISM band! We used to spend a lot of effort getting that aspect of our kit certified. HTH. -- Cheers, Steelpillow (Talk) 20:37, 8 July 2008 (UTC)[reply]

As to why microwave ovens operate at around 2.4 MHz, it was a compromise between several factors: the frequencies at which water and fats are effective absorbers, the bands not already in use for say radar, and the size of a cheap, practical magnetron with the required power output. -- Cheers, Steelpillow (Talk) 20:37, 8 July 2008 (UTC)[reply]

Later on, in the modern scramble for bandwidth, people noticed that in practice, ISM emissions are by nature intermittent, both temporally and geographically, and the quiet bits in between represented wasted bandwidth. Then someone came up with a system that they reckoned could work around the problem, so they were allowed to (I'm not even sure if they could have been stopped). -- Cheers, Steelpillow (Talk) 20:47, 8 July 2008 (UTC)[reply]

Alas, I see this same misconception in the microwave oven article. What should we do about it? --68.0.124.33 (talk) 04:11, 13 July 2008 (UTC)[reply]

Mainly, we need to do our homework: the true history is probably more complicated. Maybe the ISM bands and their early adopters kind of grew up together. I lost my notes ages ago and t'interweb thingy hasn't much to say on the history before the extension to unlicensed communications in the 1980's. Anyone with a long memory watching? -- Cheers, Steelpillow (Talk) 12:03, 13 July 2008 (UTC)[reply]

I posted a comment to Talk:ISM band and Talk:Microwave oven, hoping to catch the attention of someone who has some references. --68.0.124.33 (talk) 04:14, 14 July 2008 (UTC)[reply]

While I cannot answer the chicken and egg argument as to which came first, if you look at this ref [1] from the microwave oven article, you'll see that the microwave ISM bands date back to at least 1965. Caerwine Caer’s whines 17:28, 15 July 2008 (UTC)[reply]

Victim of the Big Bang

The Discovery of cosmic microwave background radiation, the fading remnants of the Big Bang, famously occurred as the result of it causing RF noise interference (RFI) in a sensitive microwave antenna. That, by any other name, is an EMC issue: the Big Bang was the source, the Universe the coupling path, and the microwave receiver the victim. Today, any microwave system operating in this regime must cope with RFI originating from the Big Bang (except of course for those designed to measure it). -- Cheers, Steelpillow (Talk) 20:51, 7 August 2008 (UTC)[reply]

Yes, after I reverted the edit i got the idea that this what you were referring to, In that sense you are right, although normally we mean by EMI something where there is an immediate cause and effect, so when I am pedantic I would say that the background noise is the perpetrator and all systems that suffer from micro-golf radiation noise are the "victims". The first victims were, when I remember correctly, the guys who had to remove pigeon sh*t from their micro-golf antenna because they could not figure out where the noise they received was coming from, I call that being victimised :-) Mahjongg (talk) 21:35, 7 August 2008 (UTC)[reply]

Links to commercial web sites

Links to commercial web sites are in general against Wkipedia policy. If you feel that they ought to be in this article, please discuss before posting them. -- Cheers, Steelpillow (Talk) 09:24, 8 August 2008 (UTC)[reply]

Yes, commercial links are discouraged by the WP:LINKSTOAVOID guideline.

Please tell me if there is any other policy against them (preferably with a direct link to the specific policy).

Thank you. --68.0.124.33 (talk) 04:01, 9 August 2008 (UTC)[reply]

I know of no better guideline/policy. In the above guideline, Links normally to be avoided include at #5, "Links to sites that primarily exist to sell products or services ...". So I think that a simple list of links is not a good idea.

But we must also bear in mind the Ignore all rules policy if it makes Wikipedia better. A list of equipment manufacturers and the kind of kit that they specialise in might be useful. It could then include links to websites, I think that would be reasonable. The list would need to have a global focus and not be specific to say the USA.

If you can create a user account for yourself, that would give you a Talk page where I could have contacted you earlier. I am afraid that my reflex is to revert without thinking any commercial links posted by IP (not logged in) users, as these have up to now invariably been blatant spam. I may have have been too blunt on this occasion; my apologies. -- Cheers, Steelpillow (Talk) 08:13, 9 August 2008 (UTC)[reply]

I've moved it here (below) while we decide what to do with it. -- Cheers, Steelpillow (Talk) 19:51, 11 August 2008 (UTC)[reply]

Basically, it needs to be turned into a list of Wikipedia internal links. Each individual company article can then link to their web site. -- Cheers, Steelpillow (Talk) 20:00, 11 August 2008 (UTC)[reply]

EMC test equipment manufacturer (alphabetic)

It seems redundant to have basically the same list of companies both here and in the spectrum analyzer article. Is that because spectrum analyzers are often used for EMC testing? Or do they all also (coincidentally) sell some other sort of "electromagnetic compatibility tester" device(s)? If we need this list at all, which of these 2 articles is the better place for it?

There seems to be a slow-moving revert battle between

(a) a list of manufacturers, linked to each manufacturer's Wikipedia article, vs.
(b) a slightly longer list of manufacturers, linked to each manufacturer's web site -- longer because it includes a few manufacturers that don't yet have a Wikipedia article (perhaps because they are not yet notable enough).

Would it be OK if we compromised?

(c) The slightly longer list, linked to each manufacturer's Wikipedia article (if it exists), otherwise linking to the manufacturer's web site.

I think this compromise is supported by a current guideline (WP:N#NCONTENT): some things may be important enough to mention in an article, even if they are not quite notable enough for an article of their own.

Rather than linking to the home page of the manufacturer, I think it would be even better to deep-link to some page that gave information about electromagnetic compatibility. --68.0.124.33 (talk) 02:57, 26 August 2008 (UTC)[reply]

Hi, glad you are at last making contact (if you create a user account for yourself and log in when you visit, this will become much easier).

Notability is not the issue here. Linking to commercial web sites is in general against Wikipedia guidelines (see above). It is allowed in a few cases, for example in an article about a company, a link to that company's web site is allowed. In other articles, any link should be an internal link to the Wikipedia article about that company. If there is no such article, then an entry is a good thing but it should not be linked (except maybe to a nonexistent article, so as to draw attention to the need for it). This is why we have been reverting your changes. Looks like we need to pay a visit to the spectrum analyser article, too. -- Cheers, Steelpillow (Talk) 19:48, 26 August 2008 (UTC)[reply]

As far as I can tell, the only relevance these manufacturers have to do with "electromagnetic compatibility" is that they sell spectrum analyzers, and spectrum analyzers sometimes are used to check electromagnetic compatibility. So I am moving the "EMC test equipment manufacturers (alphabetic)" section from Electromagnetic compatibility to Spectrum analyzer#Manufacturers (alphabetic).

If you want to revert, please point out how any of them "manufacture" "electromagnetic compatibility" other than by selling spectrum analyzers. Thank you. --68.0.124.33 (talk) 03:32, 14 September 2008 (UTC)[reply]

I don't know guys, there is a huge difference between a spectrum analyzer and measurement receivers used for EMC compatibility testing. A spectrum analyzer may be used for precompliance testing (a quick check before sending to a accredited test lab). In fact, most spectrum analyzers are not suitable for compliance testing. Rhode & Schwarz, Teseq and a bunch others make receivers with the resolution, bandwidths and special features needed. AutoElectric (talk) 06:59, 7 April 2009 (UTC)[reply]

Here is some reading about the differences. Its fairly technical, but important. ^[1] —Preceding unsigned comment added by AutoElectric (talk • contribs) 07:03, 7 April 2009 (UTC)[reply]

Many of these companies also sell specialist oscilloscopes and other test equipment used in EMC testing. AirMagnet is a marginal case, so I will restore the others. -- Cheers, Steelpillow (Talk) 09:25, 14 September 2008 (UTC)[reply]

References

^ http://www.ieee.li/pdf/essay/receiver_v_sa.pdf

Filter page or project

How about a project on electromagnetic compatibility/RFI filters, there uses and the firms that make them like DICRO Oy, Procond Oy, Sony and General Electric.--86.29.250.47 (talk) 19:23, 19 February 2009 (UTC)[reply]

I like the idea. I'm more of a simulation guy, however. And don't forget Schaffner for filters. —Preceding unsigned comment added by AutoElectric (talk • contribs) 06:36, 7 April 2009 (UTC)[reply]

Automotive Section or Separate Stub

I propose also a section for automotive testing. In automotive EMC, the whole vehicle is tested for RF immunity(susceptibility) and emissions. Additionally it is required to test all subassemblies both for Radiated and Transient emissions and immunty. It seems a broad subject to cover in this already long article. Opinions? AutoElectric (talk) 06:52, 7 April 2009 (UTC)[reply]

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Userbox

There is now an EMC userbox. Just add this to your user page:

{{User EMC}}

— Cheers, Steelpillow (Talk) 13:35, 6 October 2014 (UTC)[reply]

External links modified

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[1] ttp://www.ieee.li/pdf/essay/receiver_v_sa.pdf

[1]