§ 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]

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