Spectral Energy Distribution of Radio Link FM

The series expansion for the energy distribution of quasi-niose-modulated and arbitrarily preemphasized FM signals is being derived. Computer evaluations for the CCIR multichannel preemphasis in the range applicable to systems between 12- and 1800-channel loading show that not the total phase deviation but the deviation ηtopof the upper baseband portion is the quantity governing the energy density beyond 1.5 times base bandwidth off the carrier frequency. The interference into the adjacent channel is computed and a channel spacing formula is deducted based on an interference level equivalent to 3 pW. The formula is , where is the highest baseband frequency, a factor between 0 and 1, and the peak frequency deviation obtained with peak factor of 9 dB.