Sec.  15.215   Additional provisions to the general radiated emission limitations.

   (a) The regulations in  Sec.  Sec. 15.217 through 15.257 provide alternatives to the
   general radiated emission limits for intentional radiators operating in
   specified  frequency  bands.  Unless  otherwise  stated,  there are no
   restrictions as to the types of operation permitted under these sections.

   (b) In most cases, unwanted emissions outside of the frequency bands shown
   in these alternative provisions must be attenuated to the emission limits
   shown in  Sec. 15.209. In no case shall the level of the unwanted emissions from
   an intentional radiator operating under these additional provisions exceed
   the field strength of the fundamental emission.

   (c) Intentional radiators operating under the alternative provisions to the
   general emission limits, as contained in  Sec.  Sec. 15.217 through 15.257 and in
   Subpart E of this part, must be designed to ensure that the 20 dB bandwidth
   of the emission, or whatever bandwidth may otherwise be specified in the
   specific rule section under which the equipment operates, is contained
   within the frequency band designated in the rule section under which the
   equipment is operated. The requirement to contain the designated bandwidth
   of the emission within the specified frequency band includes the effects
   from frequency sweeping, frequency hopping and other modulation techniques
   that may be employed as well as the frequency stability of the transmitter
   over expected variations in temperature and supply voltage. If a frequency
   stability is not specified in the regulations, it is recommended that the
   fundamental  emission  be  kept within at least the central 80% of the
   permitted  band  in  order  to minimize the possibility of out-of-band
   operation.

   [ 54 FR 17714 , Apr. 25, 1989, as amended at  62 FR 45333 , Aug. 27, 1997;  67 FR 34855 , May 16, 2002;  69 FR 3265 , Jan. 23, 2004;  70 FR 6774 , Feb. 9, 2005]