User's Manual Chapter 13

Chapter 8: Parts List/Tune Up Information
AT&T Wireless Services
8-191
FCC Type Acceptance Application
10991 Rev. 1.0 7/6/99
Gaussian curve, most likely due to quantization errors in the
instrument.
The 4 MHz noise stimulus depicted in Figure 8.3 was injected into the
Bosch TRX unit, which up-converts its 4 MHz input IF to the Base
Station operating frequency. The TRX output was then applied to the
DUT. The DUT output signal was sampled through a -20 dB directional
coupler which fed the input to the 89441A VSA. The output level of the
NC6105 Noise Generator was adjusted to obtain an average output
power (in the time domain) of +34 dBm (2.5 Watts) at the output of the
DUT. After obtaining 1x10
6
samples of the base station output signal, a
CCDF was plotted at this operating level. The results of this test for a
typical DUT are depicted in Figure 8.4.
Figure 8.4 LPA #1 CCDF of Bandlimited Gaussian Noise Stimulus at DUT
Output, +34 dBm Average Power
As Figure 8.4 indicates, at an output power of +34 dBm, the DUT’s
output noise distribution follows the ideal Gaussian curve down to a 1%
likelihood of occurrence, where it begins a minimal departure from the
curve due to very slight compression in the transmitter chain. However,
even at a 0.001% likelihood of occurrence, the DUT curve departs from
the ideal Gaussian curve by only about 0.5 dB