Sec.  15.503   Definitions.

   (a) UWB bandwidth. For the purpose of this subpart, the UWB bandwidth is the
   frequency band bounded by the points that are 10 dB below the highest
   radiated emission, as based on the complete transmission system including
   the antenna. The upper boundary is designated f[H] and the lower boundary is
   designated f[L]. The frequency at which the highest radiated emission occurs
   is designated f[M].

   (b) Center frequency. The center frequency, f[C], equals (f[H] + f[L])/2.

   (c) Fractional bandwidth. The fractional bandwidth equals 2(f[H]−f[L])/
   (f[H]+ f[L]).

   (d) Ultra-wideband (UWB) transmitter. An intentional radiator that, at any
   point in time, has a fractional bandwidth equal to or greater than 0.20 or
   has a UWB bandwidth equal to or greater than 500 MHz, regardless of the
   fractional bandwidth.

   (e) Imaging system. A general category consisting of ground penetrating
   radar systems, medical imaging systems, wall imaging systems through-wall
   imaging systems and surveillance systems. As used in this subpart, imaging
   systems do not include systems designed to detect the location of tags or
   systems used to transfer voice or data information.

   (f) Ground penetrating radar (GPR) system. A field disturbance sensor that
   is designed to operate only when in contact with, or within one meter of,
   the ground for the purpose of detecting or obtaining the images of buried
   objects or determining the physical properties within the ground. The energy
   from the GPR is intentionally directed down into the ground for this
   purpose.

   (g) Medical imaging system. A field disturbance sensor that is designed to
   detect the location or movement of objects within the body of a person or
   animal.

   (h) Wall imaging system. A field disturbance sensor that is designed to
   detect the location of objects contained within a “wall” or to determine the
   physical properties within the “wall.” The “wall” is a concrete structure,
   the side of a bridge, the wall of a mine or another physical structure that
   is dense enough and thick enough to absorb the majority of the signal
   transmitted by the imaging system. This category of equipment does not
   include products such as “stud locators” that are designed to locate objects
   behind gypsum, plaster or similar walls that are not capable of absorbing
   the transmitted signal.

   (i) Through-wall imaging system. A field disturbance sensor that is designed
   to detect the location or movement of persons or objects that are located on
   the other side of an opaque structure such as a wall or a ceiling. This
   category of equipment may include products such as “stud locators” that are
   designed to locate objects behind gypsum, plaster or similar walls that are
   not thick enough or dense enough to absorb the transmitted signal.

   (j) Surveillance system. A field disturbance sensor used to establish a
   stationary RF perimeter field that is used for security purposes to detect
   the intrusion of persons or objects.

   (k) EIRP. Equivalent isotropically radiated power, i.e., the product of the
   power supplied to the antenna and the antenna gain in a given direction
   relative to an isotropic antenna. The EIRP, in terms of dBm, can be
   converted to a field strength, in dBuV/m at 3 meters, by adding 95.2. As
   used in this subpart, EIRP refers to the highest signal strength measured in
   any direction and at any frequency from the UWB device, as tested in
   accordance with the procedures specified in  Sec. 15.31(a) and 15.523 of this
   chapter.

   (l) Law enforcement, fire and emergency rescue organizations. As used in
   this subpart, this refers to those parties eligible to obtain a license from
   the FCC under the eligibility requirements specified in  Sec. 90.20(a)(1) of this
   chapter.

   (m) Hand held. As used in this subpart, a hand held device is a portable
   device, such as a lap top computer or a PDA, that is primarily hand held
   while being operated and that does not employ a fixed infrastructure.