Performing SAE J551d radio interference testing of automotive vehicles using the programmed automatic spectrum analyzer

The use of the new computer controlled automatic spectrum analyzer brings "instant" analysis to SAE J551d radio interference measurements. The testing company can now provide immediate answers to the manufacturers associated with the automotive industry on how to economically reduce radio interference levels emanating from their products. In order to bring the automatic testing of RF interference into proper perspective, a brief history of automotive RF interference and the beginnings of SAE J551 will be presented. Measurement techniques beginning with manual recordings on an individual frequency basis, then advancing to semi-automatic X-Y plotting on an octave by octave basis, to automatic X-Y plotting and finally to the computerized automatic spectrum analyzer with finalized semi-log charts ready for report presentation will be described. This paper will compare various measurement methods to show the advantages and disadvantages of each.