§  15.215   Additional provisions to the general radiated emission
limitations.

   (a) The regulations in § § 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 § 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 § § 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]