History of Electromagnetic Compatibility

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History of Electromagnetic Compatibility

In 2007 researchers at the University of Amsterdam published a study in which they recorded nearly 50 incidents of electromagnetic interference from mobile phone use in hospitals. Of these incidents about 75% were classified as significant or hazardous. These problems relating to electromagnetic compatibility (EMC) are not isolated to hospitals. Every year people die and significant amounts of revenue are lost resulting from EMC problems.

EMC problems have risen in the past decade due to the proliferation of microprocessors in today's devices such as mobile phones. But EMC problems first started to appear when the microprocessor were not yet conceived. And different rulings and standards have been around for a couple of decades. In this blog we’d like to take a quick look at the beginnings of EMC and give you a brief overview of it’s history.

EMC, the first radio transmitters, and the Navy

In 1859 radio pioneer Guglielmo Marconi developed the wireless telegraph. This was the first communications device that send information over radio waves. At the time this invention’s significance was not appreciated by the general public as it is today. The U.S. Military, however, saw great potential in it’s use as a communication device for their ships.

The U.S. Navy started using the wireless telegraph in 1899 and encountered one of the first known EMC problems. Because the transmitters were all tuned to the same operating frequency, no intelligible information could be received when operating more than one transmitter at the same time. This problem was dubbed Radio Frequency Interference (RFI).

Popularity of home radios and the first EMC regulations

During the start of the 20th century the first EMC regulations were being issued. To reduce the problem of RFI, different frequencies were assigned to private radio stations and the Navy. On the technical side, transmitters were being developed with increasingly more narrow bandwidths. This and other technological developments made it possible to transmit clear human speech and remarked the start of the golden age of broadcasting.

In order to tackle the problem of EMC, which were a result of the increasing popularity of radio, the Federal Communications Commission (FCC) was established. This institution was tasked to regulate all communication by radio, wire, and cable. FCC regulations caused a significant reduction of RFI problems, but new problems started developing when the general public started making use of electrical appliances.

EMC during and following World War II

During World War II new types of radio transmitters and receivers were being developed to be used in the war. Because of the immediacy of wartime, no extensive test were conducted and the equipment caused severe EMC problems on ships and planes as a result. At the end of the war the Navy issued the first RFI standard and EMC became a respected engineering specialization. In 1954 the Armour Research Foundation Conference on Radio Frequency Interference debuted. This conference still exists today under the name Electromagnetic Compatibility Society of the Institute of Electrical and Electronics Engineers (IEEE).

Intel 4004 - first commercial microprocessor

The birth of the microprocessor and the personal computer

In the 1970’s, microprocessors started to appear in consumer devices. These proliferated because of the low development costs, but also caused new EMC problems brought by the more sensitive circuits. These developments resulted in even more focus on the prevention of EMC problems. In the 1970’s a number of guidelines and standards were created to tackle the problems caused by all these new electronic devices.

In the 1980’s the rise of the personal computer brought new EMC problems to the front, but also gave engineers the computing power to analyze and solve these problems. Both the FCC and the European Union adapted extensive EMC regulations to reduce the transmission of unintentional emissions from electronic devices. Company’s were forced to start thinking about EMC in the design process of their products. Out of this and entire new industry was born. New test procedures and standards were being created and resulted in a significant reduction of EMC related problems.

Future of electromagnetic compatibility

With electronic devices getting smaller, faster, and increasingly more complex, EMC engineers face new challenges every day. New trends suggest EMC is given more importance around the world. Worldwide standards are being transposed on countries and test requirements increase. A design with EMC considered in mind is becoming the norm rather than an annoying afterthought.


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