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Radio frequency interference (RFI), is a major problem in our world of cellphones and wireless gadgets. US federal law is very specific about electronics being ''electromagnetic compatible'' with other products. [http://www.i-spec.com/EMC/usa.html FCC Part 15] testing must be performed on any product having switching frequencies of more than 9 kHz in internal circuitry, including any device using a microprocessor. Commercial equipment must meet the Class A standard, while consumer products like small computers have to meet the more stringent Class B standard. A device that radiates a lot of wide-band RF noise, like a microprocessor-based music synth, could interfere with radio communications or broadcasting. Not only could interference cause lawsuits, it could cause criminal liability, by interfering with emergency services and their two-way radio communications.
Testing usually involves a RF-shielded chamber, sometimes an "[[anechoic" chamber]] to avoid measurement errors due to acoustic noise. Special antennae, and a [[spectrum analyzer]] capable of testing to 4 GHz, are mandatory. [http://www.ee.calpoly.edu/%7Edarakaki/Paper2.pdf This paper] (PDF) describes the basic procedure. To make regulators and attorneys happy, itIt should be conducted by an "approved" testing lab. Such labs are often the same companies that perform electrical-safety certification, and they sometimes offer manufacturers "special pricing" for testing packages. But forFor a small firm, this testing can still be very costly and difficult to justify for low-production products like synthesizers. FCC Part 15 testing for a single product can easily cost $8,000 or up.
It is possible to perform your own FCC Part 15 tests, by setting up equipment in a rural field, well away from any sources of RF energy. But the test equipment needed is still costly, some knowledge of EMC testing is needed, and the engineer runs the risk of having his tests invalidated in court, because he wasn't "certified". What does "certified" mean? Apparently, it means whatever the FCC and the courts want to say it means. The FCC does not perform actual certification of test labs, they leave it to the "free market", meaning to liability attorneys. So, even settingSetting up a test lab iscan be more an exercise in public relations and maintaining an image of "reliability" and "seriousness" than it is an actual measure of technical ability.
To sell the same product in Europe, IEC 61000 testing is required to certify it for a CE mark. The CE mark simply states that the product has been tested, meets the EU standard, and is legally permitted to be sold in Europe. Needless to say, the IEC test is similar to the FCC Part 15 test, but different enough to make separate testing unavoidable. This typically costs $15,000-$20,000 for each separate product, in the USUSA. The regulation also says that [[ESD]] (electrostatic discharge) testing is mandatory, to assure the product will not be damaged by static discharge from the user.
Other countries have their own EMC regulations, test conditions, and certifications. Japan has the [http://www.ce-mag.com/99ARG/Gubisch145.html VCCI] regulation, requiring separate testing but only by a VCCI-registered test lab. In Russia tests for the [http://www.sgs.com/safety_v2/gost_r_mark.htm GOST-R mark] can be carried out outside the country and then exported to Russia with few problems.
Searching online for information about EMC often leads to the websites of the test labs. Wherein they advertise and brag about their capabilities, but provide very little hard information. Textbooks about RFI/EMC exist but are usually out of print and difficult to find (luckily, some can be [http://books.google.com/books/about/The_technician_s_EMI_handbook.html?id=PImqHW34Bt0C found] on Google Books). Reading them usually requires some formal education in electronics, including radio propagation and advanced math.
Again, some other countries have their own EMC regulations, test conditions, and certifications. Japan has a similar [http://www.ce-mag.com/99ARG/Gubisch145.html regulation], also requiring separate testing, but only by a VCCI-registered test lab. I've heard that in Russia, all that's needed to get a [http://www.sgs.com/safety_v2/gost_r_mark.htm GOST-R mark] is a suitable bribe. You can test for it outside Russia, then export to Russia with few problems. But a bribe can be far cheaper and easier to do, provided you know who the actual bribe must go to. Similar things happen in countries like Brazil, India and China. Italy is long notorious for having problems with corruption among its customs officials, even for small shipments of commercial goods. And parts of Africa, like Nigeria or Zimbabwe, are an insane nightmare to export to.
So far, modular synthesizers have been too low in production to attract the attention of EMC regulators, in the US, in Japan or in the EU. And the "kit" aspect of a modular synth might serve to invalidate EMC regulations, similarly to electrical-safety standards. However, I have not been able to find court cases that will confirm this. The fact that most modules were analog (containing no RFI-generating microprocessors or other such circuits) in the past has been an advantage, since Part 15 simply doesn't apply to them. With the appearance of DSP-based or microprocessor-based modules in recent years, that could change. A legal challenge to the modular synth has not occurred to date. ▼
▲So far, modular synthesizers have been too low in production to attract the attention of EMC regulators, in the US, in Japan or in the EU. And theThe "kit " aspect of a modular synth might serve to invalidate EMC regulations, similarly to electrical-safety standards . However, I have not been able to find court cases that will confirm this. The fact that most modules were analog (containing no RFI-generating microprocessors or other such circuits) in the past has been an advantage, since Part 15 simply doesn't apply to them. With the appearance of [[DSP ]]-based or microprocessor-based modules in recent years, that could change. A legal challenge to the modular synth has not occurred to date.
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