Radio interference and test methods

The problem of radio interference generated by the car itself will occur increasingly as the electronic complexity of motor vehicles rises. There was a leap in the quantity and type of technology employed in motor vehicles which happened with the launch of such cars as the new BMW 7 Series, the new Jaguar XJ6 and the new Opel Senator. From cars with, perhaps, engine management and a trip computer, our industry has jumped straight to cars routinely containing 7 or more microprocessors. Since susceptibility to, and generation of, radio energy seem to be poorly understood by hardware engineers, it appears that this aspect of component design has been largely ignored. Understanding the mechanisms involved requires a knowledge of both antenna and transmission line engineering. Until recently, problems in this area have been rectified as they have manifested themselves at a stage in design too late to influence fundamentals such as board layout and logic choice. Some test methods are outlined which allow detection of problems early in the design cycle