§ 15.521   Technical requirements applicable to all UWB devices.

   (a) UWB devices may not be employed for the operation of toys. Operation
   onboard an aircraft, a ship or a satellite is prohibited.

   (b) Manufacturers and users are reminded of the provisions of § § 15.203 and
   15.204.

   (c) Emissions from digital circuitry used to enable the operation of the UWB
   transmitter shall comply with the limits in § 15.209, rather than the limits
   specified in this subpart, provided it can be clearly demonstrated that
   those emissions from the UWB device are due solely to emissions from digital
   circuitry contained within the transmitter and that 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 UWB transmission, are subject to the limits contained in Subpart B
   of this part.

   (d) Within the tables in § § 15.509, 15.511, 15.513, 15.515, 15.517, and
   15.519, the tighter emission limit applies at the band edges. Radiated
   emission levels at and below 960 MHz are based on measurements employing a
   CISPR quasi-peak detector. Radiated emission levels above 960 MHz are based
   on RMS average measurements over a 1 MHz resolution bandwidth. The RMS
   average  measurement is based on the use of a spectrum analyzer with a
   resolution bandwidth of 1 MHz, an RMS detector, and a 1 millisecond or less
   averaging time. Unless otherwise stated, if pulse gating is employed where
   the transmitter is quiescent for intervals that are long compared to the
   nominal pulse repetition interval, measurements shall be made with the pulse
   train gated on. Alternative measurement procedures may be considered by the
   Commission.

   (e) The frequency at which the highest radiated emission occurs, fM, must be
   contained within the UWB bandwidth.

   (f)  Imaging  systems may be employed only for the type of information
   exchange described in their specific definitions contained in § 15.503. The
   detection  of tags or the transfer or data or voice information is not
   permitted under the standards for imaging systems.

   (g)  When  a  peak  measurement is required, it is acceptable to use a
   resolution bandwidth other than the 50 MHz specified in this subpart. This
   resolution bandwidth shall not be lower than 1 MHz or greater than 50 MHz,
   and the measurement shall be centered on the frequency at which the highest
   radiated emission occurs, fM. If a resolution bandwidth other than 50 MHz is
   employed, the peak EIRP limit shall be 20 log (RBW/50) dBm where RBW is the
   resolution bandwidth in megahertz that is employed. This may be converted to
   a peak field strength level at 3 meters using E(dBuV/m) = P(dBm EIRP) +
   95.2. If RBW is greater than 3 MHz, the application for certification filed
   with  the  Commission  must contain a detailed description of the test
   procedure, calibration of the test setup, and the instrumentation employed
   in the testing.

   (h) The highest frequency employed in § 15.33 to determine the frequency
   range over which radiated measurements are made shall be based on the center
   frequency, fC, unless a higher frequency is generated within the UWB device.
   For measuring emission levels, the spectrum shall be investigated from the
   lowest frequency generated in the UWB transmitter, without going below 9
   kHz, up to the frequency range shown in § 15.33(a) or up to fC + 3/(pulse
   width in seconds), whichever is higher. There is no requirement to measure
   emissions beyond 40 GHz provided fC is less than 10 GHz; beyond 100 GHz if
   fC is at or above 10 GHz and below 30 GHz; or beyond 200 GHz if fC is at or
   above 30 GHz.

   (i) The prohibition in § 2.201(f) and 15.5(d) of this chapter against Class B
   (damped wave) emissions does not apply to UWB devices operating under this
   subpart.

   (j) Responsible parties are reminded of the other standards and requirements
   cross referenced in § 15.505, such as a limit on emissions conducted onto the
   AC power lines.

   [ 67 FR 34856 , May 16, 2002, as amended at  68 FR 19751 , Apr. 22, 2003;  70 FR 6776 , Feb. 9, 2005]

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