ITU-R REPORT BS.1065
The RF spectrum of frequency-modulation sound-broadcasting transmitters
Organization: | ITU-R |
Publication Date: | 1 January 1986 |
Status: | active |
Page Count: | 6 |
scope:
Introduction
The RF spectrum of frequency-modulation
Rules for the calculation of the necessary bandwidth of emission
for numerous services are laid down in the Radio Regulations and
examples are given in Appendix 6 to these Regulations. According to
these rules the necessary bandwidth of frequency-modulation
Measurement results particularly when obtained for stereophonic emissions, differ greatly from the calculated values. [n the light of Report 418 it is rather doubtful whether Carson's rule may be used in bandwidth calculations for stereophonic emissions, since the pre-supposition that Dยป fmax is not met, and since consequently. a value K ≠1 may have to be used.
Difficulties are also experienced when calculating the occupied bandwidth and also the out-of-band emissions. For example no reference to out-of-band emissions in FM sound broadcasting is contained in Recommendation 328 "Spectra and bandwidths of emissions", although out-of-band emissions are defined there. Even Reports 275 and 324, which are quoted in the Recommendation and which deal with measurements of bandwidths of emissions. do not include any useful information with respect to this question. Measurements of the frequency spectrum of transmitters which are frequency-modulated with white noise are described in Report 977. However, the results of these measurements do not permit conclusions to be made with regard to the radio-frequency spectrum of frequency modulation sound-broadcasting transmitters. [t was with this in mind that the measurements described below were performed [CCI R, 1982-86a].