User's Manual Chapter 13

Chapter 8: Parts List/Tune Up Information
AT&T Wireless Services
8-187
FCC Type Acceptance Application
10991 Rev. 1.0 7/6/99
8.3 Base Station RF Power Output Limiting
8.3.0.1 Applicable FCC Rules
FCC Subpart 24.232(b) -....In no case may the peak output power of a
base station transmitter exceed 100 watts.
FCC Subpart 24.232(c)-Peak transmitter power may be measured over
any interval of continuous transmission using instrumentation
calibrated in terms of RMS equivalent voltage. The measurement
results shall be properly adjusted for any instrument limitations, such as
detector response times, limited resolution bandwidth capability when
compared to the emission bandwidth, sensitivity, etc., so as to obtain a
true peak measurement for the emission in question over the full
bandwidth of the channel.
8.3.0.2 Overview
The PWAN Linear Power Amplifier (LPA) was designed to provide
linear operation within a 12 dB peak-average ratio, based on a nominal
average output power of +34 dBm (2.5 Watts). In order to support the
12 dB peak/average ratio required for OFDM service, the PWAN LPA
must be capable of providing a peak output power of at least +46 dBm
(40 Watts). The tests included in this section were designed to
statistically characterize the peak output power of the PWAN LPA in
order to assure compliance with the 100 Watt power limitation
stipulated in 24.232(b).
8.3.0.3 Test Methodology
Because the objective of this test was to determine the statistical peak
output power (and the associated clipping level) of the PWAN LPA, a
description of output power vs. likelihood of occurrence was desired. In
addition, a test stimulus that approximates the characteristics of the
PWAN OFDM signal seemed most appropriate. For this test, a signal
with a known statistical distribution was utilized as the stimulus for the
LPA under test. Comparison of the input and output signal distributions
provided a means of determining the linearity of the LPA under test, as
well as a statistical description of peak output power vs. likelihood of
occurrence.
The Hewlett-Packard 89441A Vector Signal Analyzer is capable of
providing the user with a Complimentary Cumulative Distribution