User's Manual Chapter 13

Base FCC Regulatory Test Report
8-192
AT&T Wireless Services
FCC Type Acceptance Application
10991 Rev. 1.0 7/6/99
After establishing the linearity of the DUT at a normal operating power
of +34 dBm, the noise generator was readjusted to provide an average
output power of +40 dBm (6 dB above normal operating level) at the
DUT output. This level was chosen because it was high enough to test
the clipping characteristics of the DUT and low enough to prevent
tripping the DUT’s internal overpower sensor. The results of this test
for a typical DUT are depicted in Figure 8.5.
Figure 8.5 LPA #1 CCDF of Bandlimited Gaussian Noise Stimulus at DUT
Output, +40 dBm Average Power
As Figure 8.5 indicates, the DUT output follows the ideal Gaussian
curve down to a 10% likelihood of occurrence, at which point it
dropped precipitously, indicating clipping in the DUT. At 0.1%
likelihood of occurrence, the DUT displayed about 2 dB of clipping. At
a 0.001% likelihood of occurrence, the peak-average ratio for the DUT
depicted in Figure 8.5 was approx. 6.5 dB (about 3.5 dB of clipping).
As a result of this test, we can conclude that 99.999% of the time the
DUT depicted in Figure 8.5 is incapable of generating a peak output
power in excess of +46.5 dBm (44.7 Watts).
In an effort to verify the repeatability of these results among several
DUTs and TRX units, tests on a total of seven DUTs fed by one of two
different TRX units were executed. A tabulation of the test results is
shown in Table 8.4— below. The test plots depicted in Figure 8.4 and
Figure 8.5 are typical of the seven DUTs.