Goto Section: 30.403 | 30.405 | Table of Contents
FCC 30.404
Revised as of October 1, 2020
Goto Year:2019 |
2021
§ 30.404 Emission limits.
(a) The mean power of emissions must be attenuated below the mean
output power of the transmitter in accordance with the following
schedule:
(1) When using transmissions other than those employing digital
modulation techniques:
(i) On any frequency removed from the assigned frequency by more than
50 percent up to and including 100 percent of the authorized bandwidth:
At least 25 decibels;
(ii) On any frequency removed from the assigned frequency by more than
100 percent up to and including 250 percent of the authorized
bandwidth: At least 35 decibels;
(iii) On any frequency removed from the assigned frequency by more than
250 percent of the authorized bandwidth: At least 43 + 10 Log10 (mean
output power in watts) decibels, or 80 decibels, whichever is the
lesser attenuation.
(2) When using transmissions employing digital modulation techniques in
situations not covered in this section:
(i) In any 1 MHz band, the center frequency of which is removed from
the assigned frequency by more than 50 percent up to and including 250
percent of the authorized bandwidth: As specified by the following
equation but in no event less than 11 decibels:
A = 11 + 0.4(P-50) + 10 Log10 B. (Attenuation greater than 56 decibels
or to an absolute power of less than -13 dBm/1MHz is not required.)
(ii) In any 1 MHz band, the center frequency of which is removed from
the assigned frequency by more than 250 percent of the authorized
bandwidth: At least 43 + 10 Log10 (the mean output power in watts)
decibels, or 80 decibels, whichever is the lesser attenuation. The
authorized bandwidth includes the nominal radio frequency bandwidth of
an individual transmitter/modulator in block-assigned bands. Equipment
licensed prior to April 1, 2005 shall only be required to meet this
standard in any 4 kHz band.
(iii) The emission mask in paragraph (a)(2)(i) of this section applies
only to the band edge of each block of spectrum, but not to subchannels
established by licensees. The value of P in the equation is the
percentage removed from the carrier frequency and assumes that the
carrier frequency is the center of the actual bandwidth used. The
emission mask can be satisfied by locating a carrier of the subchannel
sufficiently far from the channel edges so that the emission levels of
the mask are satisfied. The emission mask shall use a value B
(bandwidth) of 40 MHz, for all cases even in the case where a narrower
subchannel is used (for instance the actual bandwidth is 10 MHz) and
the mean output power used in the calculation is the sum of the output
power of a fully populated channel. For block assigned channels, the
out-of-band emission limits apply only outside the assigned band of
operation and not within the band.
(b) [Reserved]
Goto Section: 30.403 | 30.405
Goto Year: 2019 |
2021
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