Mobile FM Reception: An Evaluation of the Effectiveness of FM Diversity Systems 940265
Increasing customer expectations, combined with the expanding application of high-performance media delivery systems, requires a high performance level be achieved for automotive FM reception with the existing analog broadcast technology. Multipath distortion is often cited as a leading industry concern that can limit the quality of mobile FM reception.
FM diversity has been identified as a potential methodology for improving the reception performance under multipath conditions. However, the delay time and strength of any signal reflections can vary considerably under differing terrain and geographic conditions. The corresponding amplitude and phase disturbances within the transmission channel are significantly different as a function of the propagation environment. Additionally, the specific implementation strategy and architecture of the diversity system can have a significant impact on the performance effectiveness of the system.
This paper will review the spectral and transmission channel requirements for distortion free FM reception and the contamination that occurs under multipath propagation conditions. Phase calculations and antenna system measurements will attempt to quantify the relative performance improvements that might be expected with a space diversity system. Data obtained from a substantial amount of field evaluations, under different geographic conditions, will be shown to quantify the performance improvements under “real world” conditions with different diversity system architectures.