Goto Section: 15.249 | 15.251 | Table of Contents
Revised as of October 1, 2009
Goto Year:2008 |
§ 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 § 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)
(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
Frequency in MHz EIRP in dBm
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
Frequency in MHz EIRP in dBm
(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 § 15.209.
(5) Emissions from digital circuitry used to enable the operation of
the transmitter may comply with the limits in § 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
§ 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 § 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
(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
§ 15.31(c) continue to apply to transmitters that employ swept frequency
(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
[ 70 FR 6774 , Feb. 9, 2005]
Goto Section: 15.249 | 15.251
Goto Year: 2008 |
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