§  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)
   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 §  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
   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
   §  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]

   return arrow Back to Top