Volvo not disturbed by electronmagnetic interference

Cooperation with FOI was a valuable injection into our work to ensure that our cars are free from electromagnetic interference. In connection with digital developments in DAB radio, FOI has developed methods for the analysis of interference at the radio antenna input. With FOI’s expertise and resources we been able to refine our measurement methods and our cars are now safer than ever from interference, says Björn Bergqvist, Technical specialist, Volvo Car Corporation.


Everything causes interference

- When a lot of electrical equipment has to be fitted into a small envelope, such as cars, boats or aircraft, there tends to be mutual interference. Electromagnetic interference can mean that cabling and other noise-transmitting elements can cause so much interference that a radio, for example, will not function properly. Naturally it is important to know whether what one is installing is going to interfere with some other piece of equipment. Volvo Car Corporation was interested in DAB radio and in determining the limit at which DAB reception suffered from interference. This is important in view of the coming replacement of conventional analogue technology by digital transmissions.”


Military becomes civil

-There is, however, no established method of measurement that gives sufficient information about the interference environment. Just measuring power at different frequencies is not enough. At FOI, however, we have long been working on behalf of the Swedish Armed Forces and the Defence Materiel Administration (FMV) to study how sources of interference affect digital radio systems, and we have devised a better method of measuring interference. This work is virtually unique in the world and formed the basis of my doctoral thesis at Chalmers.”


International standard

-Our method is based on the so-called amplitude probability distribution (APD) of the interference environment. This is now also under discussion by CISPR, the International Special Committee on Radio Interference, as a suitable method for the specification of requirements for the protection of radio systems from the emissions of microwave ovens. We have also been called upon by other companies, for example Telekom Malaysia and research institutes in Japan.”


Most expensive is not always best

- So together with Volvo we were able to put our method to the test while they, at the same time, had a tool with which they could keep component prices down without compromising quality or safety. They can now safely choose the equipment that is best for the purpose concerned without necessarily having to buy the most expensive components. This yields substantial savings.”


“The reason why Volvo works with us at FOI is that they wish to take a proactive approach, allowing them to get ahead of the competition in this area of research, knowing that we are one of the few players worldwide that are real experts in this field. Cars contain a lot of electrical equipment concentrated in a small area. This is true, not least, for Volvo Cars who wish to maintain a technical lead in this field, and to offer their customers the best possible solutions. Although the proliferation of automotive electronic systems can lead to problems of electromagnetic compatibility, we have long experience of research in this field and had a test method ready for Volvo when they needed it.”