A Test Bench for Measuring the Sensitivity Threshold of FM Receivers in the Presence of Interference Through Direct Injection of the Radio Signal

Abstract

Evaluating the quality of radio reception is a crucial step in the production process of a vehicle. To evaluate radio reception, several parameters come into play. The radio signal depends on the nature of the electromagnetic propagation channel, the characteristics of the antennas and on the electronic reception chain. The quality of reception is also potentially affected by the interference signals generated at the RF input of the car receiver by the on-board electronics. However, current measurement methods of radio reception quality do not link these interference signals to the radio signal whose reception may be affected or not, according to the nature of interferences. This communication presents an original test bench allowing the evaluation of the quality of radio reception of a vehicle in a semi-anechoic chamber. This test bench constitutes an essential building block of a global methodological process. Its objective is to measure the sensitivity threshold of the radio reception chain (in the AM/FM/DAB bands) of the vehicle and to evaluate the evolution of this threshold as a function of the interference generated by the various components of the vehicle. We have set up two methods to carry out this experiment: injecting the radio signal directly at the input of the radio (conducted mode) and injecting the radio signal using an antenna (radiated mode). This article focuses on the conducted mode and describes the corresponding test bench. Some measurement examples are performed and discussed in the FM band.