A Test Setup to Assess the Impact of EMI Produced by On-Board Electronics on the Quality of Radio Reception in Vehicles

Radio performance is very important in the automotive industry. It is necessary to provide a careful assessment of radio reception of each vehicle project development. It is well known that the vehicle radio performance may be affected by electromagnetic interferences from the components of the vehicle itself. These interferences degrade the radio signals and prevent the on-board receiver from retrieving correctly the baseband signal. Generally, the car manufacturers rely on the international special committee on radio interference (CISPR) 25 standard to decide whether radio reception tests pass or fail according to the interference limits set in advance. However, although the standard is able to detect interferences and determine their type and level according to various detectors, their consequence on radio reception quality (if any) cannot be assessed in a quantitative manner. This is even more difficult with digital communication systems such as digital analog broadcasting (DAB). For the time being, the final quality of the radio reception is evaluated in a totally independent way, through driving tests. This article introduces an improved test setup that performs both interference level measurements and assessment of the radio reception performance. Two operating modes are described. They are based either on the conducted or the radiated injection of the transmitted radio signal. Although dedicated to analog and digital transmissions, we will deal only with the analog radio (FM) in this article. From a set of experiments, we conclude that interferences measured with average detectors are more likely correlated to radio reception issues.