FCC 15.250 Revised as of October 1, 2007
Goto Year:2006 |
2008
Sec. 15.250 Operation of wideband systems within the band 5925–7250 MHz.
(a) The −10 dB bandwidth of a device operating under the provisions of this
section must be contained within the 5925–7250 MHz band under all conditions
of operation including the effects from stepped frequency, frequency hopping
or other modulation techniques that may be employed as well as the frequency
stability of the transmitter over expected variations in temperature and
supply voltage.
(b) The −10 dB bandwidth of the fundamental emission shall be at least 50
MHz. For transmitters that employ frequency hopping, stepped frequency or
similar modulation types, measurement of the −10 dB minimum bandwidth
specified in this paragraph shall be made with the frequency hop or step
function disabled and with the transmitter operating continuously at a
fundamental frequency following the provisions of Sec. 15.31(m).
(c) Operation on board an aircraft or a satellite is prohibited. Devices
operating under this section may not be employed for the operation of toys.
Except for operation onboard a ship or a terrestrial transportation vehicle,
the use of a fixed outdoor infrastructure is prohibited. A fixed
infrastructure includes antennas mounted on outdoor structures, e.g. ,
antennas mounted on the outside of a building or on a telephone pole.
(d) Emissions from a transmitter operating under this section shall not
exceed the following equivalent isotropically radiated power (EIRP) density
levels:
(1) The radiated emissions above 960 MHz from a device operating under the
provisions of this section shall not exceed the following RMS average limits
based on measurements using a 1 MHz resolution bandwidth:
Frequency in MHz EIRP in dBm
960–1610 −75.3
1610–1990 −63.3
1990–3100 −61.3
3100–5925 −51.3
5925–7250 −41.3
7250–10600 −51.3
Above 10600 −61.3
(2) In addition to the radiated emission limits specified in the table in
paragraph (d)(1) of this section, transmitters operating under the
provisions of this section shall not exceed the following RMS average limits
when measured using a resolution bandwidth of no less than 1 kHz:
Frequency in MHz EIRP in dBm
1164–1240 −85.3
1559–1610 −85.3
(3) There is a limit on the peak level of the emissions contained within a
50 MHz bandwidth centered on the frequency at which the highest radiated
emission occurs and this 50 MHz bandwidth must be contained within the
5925–7250 MHz band. The peak EIRP limit is 20 log (RBW/50) dBm where RBW is
the resolution bandwidth in megahertz that is employed by the measurement
instrument. RBW shall not be lower than 1 MHz or greater than 50 MHz. The
video bandwidth of the measurement instrument shall not be less than RBW. If
RBW is greater than 3 MHz, the application for certification filed with the
Commission shall contain a detailed description of the test procedure,
calibration of the test setup, and the instrumentation employed in the
testing.
(4) Radiated emissions at or below 960 MHz shall not exceed the emission
levels in Sec. 15.209.
(5) Emissions from digital circuitry used to enable the operation of the
transmitter may comply with the limits in Sec. 15.209 provided it can be clearly
demonstrated that those emissions are due solely to emissions from digital
circuitry contained within the transmitter and the emissions are not
intended to be radiated from the transmitter's antenna. Emissions from
associated digital devices, as defined in Sec. 15.3(k), e.g. , emissions from
digital circuitry used to control additional functions or capabilities other
than the operation of the transmitter, are subject to the limits contained
in subpart B of this part. Emissisons from these digital circuits shall not
be employed in determining the −10 dB bandwidth of the fundamental emission
or the frequency at which the highest emission level occurs.
(e) Measurement procedures:
(1) All emissions at and below 960 MHz are based on measurements employing a
CISPR quasi-peak detector. Unless otherwise specified, all RMS average
emission levels specified in this section are to be measured utilizing a 1
MHz resolution bandwidth with a one millisecond dwell over each 1 MHz
segment. The frequency span of the analyzer should equal the number of
sampling bins times 1 MHz and the sweep rate of the analyzer should equal
the number of sampling bins times one millisecond. The provision in
Sec. 15.35(c) that allows emissions to be averaged over a 100 millisecond period
does not apply to devices operating under this section. The video bandwidth
of the measurement instrument shall not be less than the resolution
bandwidth and trace averaging shall not be employed. The RMS average
emission measurement is to be repeated over multiple sweeps with the
analyzer set for maximum hold until the amplitude stabilizes.
(2) The peak emission measurement is to be repeated over multiple sweeps
with the analyzer set for maximum hold until the amplitude stabilizes.
(3) For transmitters that employ frequency hopping, stepped frequency or
similar modulation types, the peak emission level measurement, the
measurement of the RMS average emission levels, and the measurement to
determine the frequency at which the highest level emission occurs shall be
made with the frequency hop or step function active. Gated signals may be
measured with the gating active. The provisions of Sec. 15.31(c) continue to
apply to transmitters that employ swept frequency modulation.
(4) The −10 dB bandwidth is based on measurement using a peak detector, a 1
MHz resolution bandwidth, and a video bandwidth greater than or equal to the
resolution bandwidth.
(5) Alternative measurement procedures may be considered by the Commission.
[ 70 FR 6774 , Feb. 9, 2005]
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