154 Chapter 2
Front-Panel Key Reference
MEASURE
NOTE CCDF measurement requires the installation of Option AYX or Option
B7D to ensure measurement accuracy.
For each single sweep of this measurement, the average power is
defined by:
where V is the envelope voltage, Z
0
is the characteristic impedance, and
n is the number of samples (32k maximum).
Pavg is used as a guideline to define the probability of the samples,
which is x dB above the average power. The number of samples
collected per sweep depends upon the sampling rate and the setting of
the measurement interval. Multiple sweeps may be required if the
sample number exceeds the number of samples collected per sweep. The
results and the CCDF curve are updated after every single sweep.
Results from a 2.17 GHz W-CDMA 3GPP input signal are shown below
in Figure 2-6.
NOTE It is important to set the correct center frequency before initiating this
measurement.
Figure 2-6 Power Stat CCDF Measurement Results
Pavg V
2
Z
0
⁄()
1
n
∑
n⁄=
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