§ 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. In the case of
   intentional radiators operating under the provisions of subpart E, the
   emission bandwidth may span across multiple contiguous frequency bands
   identified in that subpart. 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;  79 FR 24578 , May 1, 2014]

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