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Copyright 1999-2015

FCC Part 15 Radio Frequency Devices
Section 15.521

The Federal Communications Commission (FCC) is the authority in the United States of America that creates and enforces the use of airwaves throughout the entire radio frequency spectrum. This group of documents contains the entirety of the FCC Part 15 regulations that concern unlicensed radio frequency devices. As with all government documents, this material is in the public domain and may be freely copied so long as the content is not changed. This copy is provided as a convenience for RF Cafe visitors. 

Click here for the Table of Contents.

[Code of Federal Regulations]
[Title 47, Volume 1]
[Revised as of October 1, 2008]
From the U.S. Government Printing Office via GPO Access
[CITE: 47CFR15.521]
[Page 846-847]
                       TITLE 47--TELECOMMUNICATION
                   Subpart F_Ultra-Wideband Operation
Sec. 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 
Sec. Sec. 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 Sec. 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 Sec. 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 
    (d) Within the tables in Sec. Sec. 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 Sec. 
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 Sec. 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
[[Page 847]]
from the lowest frequency generated in the UWB transmitter, without 
going below 9 kHz, up to the frequency range shown in Sec. 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 Sec. 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 Sec. 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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