Sec.  87.135   Bandwidth of emission.

   (a) Occupied bandwidth is the width of a frequency band such that, below the
   lower and above the upper frequency limits, the mean powers emitted are each
   equal to 0.5 percent of the total mean power of a given emission.

   (b) The authorized bandwidth is the maximum occupied bandwidth authorized to
   be used by a station.

   (c) The necessary bandwidth for a given class of emission is the width of
   the frequency band which is just sufficient to ensure the transmission of
   information at the rate and with the quality required under specified
   conditions.