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ANSI C63.17-2006
Methods of Measurement of the Electromagnetic and Operational Compatibility of UPCS Devices
Independent of antenna type and placement, the measurement type (i.e., conducted or radiated) can be
selected by the product manufacturer and specified in the compliance report. Conducted measurements are
generally required for systems with detachable antennas for measurements where antenna frequency
selectivity is not a factor.
Compliance measurements utilize standard EMC and antenna techniques for conducted power, radiated
field, and EIRP measurements. The conducted test setup is based on power measurements at the EUT
transmit, receive, and monitoring antenna terminals. The associated compliance limits for the UPCS
products depend on the transmit antenna gain G
A
. The value of G
A
is declared by the manufacturer.
Since the transmitter and receiver radiated power parameters can be expressed in several different but
equivalent ways, a number of alternative compliance test procedures can be used for radiated
measurements. The general radiated test setup is based on free-space environment measurements as shown
in Figure 2, where D is the largest dimension of the EUT (see Figure 3 for the general conducted test
setup). The free-space test site is defined such that the reflections from any ground planes and other
reflecting objects are at least 10 dB below the line-of-sight signal. The reference antenna is used to measure
the EUT radiating power and to establish the monitoring threshold fields at the transmit and monitoring
antennas. The associated compliance limits are based on the EIRP. The antenna gain and the EIRP
evaluations should be performed as recommended in IEEE Std 149-1979.
Figure 2
4.3
—Radiated measurements in free-space environment
Equivalent radiated tests can be performed in facilities that do not provide for a free-space environment
and/or measure radiated power (wideband transverse electromagnetic (TEM), etc.). Instead of using the
reference antenna, the necessary power levels are generated and/or measured by the test facility itself. If
alternative measurements are used, the test results must be correlated with those obtained using antenna
measurements in a free-space environment.
Transmitted power and monitoring threshold limits
The spectrum etiquette for UPCS systems requires that one or both ends of a linked pair monitor a channel
for other users in proximity, prior to transmitting. The EUT must defer using the channel if the amount of
other-user signal detected is above a threshold. EUT systems that support a large number of users and
implement the LIC algorithm are permitted to use an upper threshold for interference; EUT systems that
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