A study of the frequency modulation distortion due to multi-path in the land-mobile environment

Radio signals in the land-mobile environment experience distortion due to reflections off of various obstacles. One method that is commonly used to characterize this distortion is to observe the resulting amplitude and frequency modulation as separate distortion components. This paper reviews the characteristics of the frequency modulation distortion and presents the results of measuring this distortion in the Fort Worth, Texas area. The results indicate that, most of the time, the distortion in the 160 MHz and 460 MHz bands is Rician rather than Rayleigh.