Sec. 22.359  Emission masks.

    Unless otherwise indicated in the rules governing a specific radio 
service, all transmitters intended for use in the Public Mobile Services 
must be designed to comply with the emission masks outlined in this 
section. If an emission outside of the authorized bandwidth causes 
harmful interference, the FCC may, at its discretion, require greater 
attenuation than specified in this section.
    (a) Analog modulation. For transmitters other than those employing 
digital modulation techniques, the mean or peak envelope power of 
adjacent channel emissions must be attenuated below the output mean or 
peak envelope power of the total emission (P, in Watts) in accordance 
with the following schedule:
    (1) On any frequency removed from the center frequency of the 
assigned channel by more than 50 percent up to and including 100 percent 
of the authorized bandwidth:

at least 25 dB:

    (2) On any frequency removed from the center frequency of the 
assigned channel by more than 100 percent up to and including 250 
percent of the authorized bandwidth:

at least 35 dB:

    (3) On any frequency removed from the center frequency of the 
assigned channel by more than 250 percent of the authorized bandwidth:

at least 43 + 10 log P dB, or 80 dB, whichever is the lesser 
attenuation.

    (b) Digital modulation. For transmitters not equipped with an audio 
low pass filter and for transmitters employing digital modulation 
techniques, the mean or peak envelope power of sideband emissions must 
be attenuated below the mean or peak envelope power of the total 
emission (P, in Watts) in accordance with the following schedule:
    (1) For transmitters that operate in the frequency ranges 35 to 44 
MHz, 72 to 73 MHz, 75.4 to 76.0 MHz and 152 to 159 MHz,
    (i) On any frequency removed from the center frequency of the 
assigned channel by a displacement frequency fd (in kHz) of 
more than 5 kHz but not more than 10 kHz:

at least 83 log (fd5) dB;

    (ii) On any frequency removed from the center frequency of the 
assigned channel by a displacement frequency fd (in kHz) of 
more than 10 kHz but not more than 250 percent of the authorized 
bandwidth:

at least 29 log fd211) dB or 50 dB, whichever is the 
lesser attenuation;

    (iii) On any frequency removed from the center frequency of the 
assigned channel by more than 250 percent of the authorized bandwidth:

at least 43 + 10 log P dB, or 80 dB, whichever is the lesser 
attenuation.

    (2) For transmitters that operate in the frequency ranges 450 to 512 
MHz and 929 to 932 MHz,
    (i) On any frequency removed from the center frequency of the 
assigned channel by a displacement frequency fd (in kHz) of 
more than 5 kHz but not more than 10 kHz:


at least 83 log (fd5) dB;

    (ii) On any frequency removed from the center frequency of the 
assigned channel by a displacement frequency fd (in kHz) of 
more than 10 kHz but not more than 250 percent of the authorized 
bandwidth:

at least 116 log (fd6.1) dB, or 50 + 10 log P dB, or 
70 dB, whichever is the lesser attenuation;

    (iii) On any frequency removed from the center frequency of the 
assigned channel by more than 250 percent of the authorized bandwidth:

at least 43 + 10 log P dB, or 80 dB, whichever is the lesser 
attenuation.

    (c) Measurement procedure. Either peak or average power may be used, 
provided that the same technique is used for both the adjacent channel 
or sideband emissions and the total emission. The resolution bandwidth 
of the measuring instrument must be set to

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300 Hz for measurements on any frequency removed from the center 
frequency of the assigned channel by no more than 250 percent of the 
authorized bandwidth and 30 kHz for measurements on any frequency 
removed from the center frequency of the assigned channel by more than 
250 percent of the authorized bandwidth.