Measurements
R&S
®
FSW
261
User Manual 1173.9411.02 ─ 19
x-axis ref level:
-10 dBm
x-axis range APD:
100 dB
x-axis range CCDF:
20 dB
y-axis upper limit:
1.0
y-axis lower limit:
1E-6
Remote command:
Adjust Settings
Adjusts the level settings according to the measured difference between peak and min-
imum power for APD measurement or peak and mean power for CCDF measurement
in order to obtain maximum power resolution. Adjusts the reference level to the current
input signal.
Remote command:
5.8.6 How to Perform an APD or CCDF Measurement
To start a basic statistic measurement
1. Press the MEAS key, then select the "APD" or "CCDF" measurement.
2. Start a sweep.
As soon as the defined number of samples have been measured, the statistical
evaluation is displayed.
To perform a statistic measurement using gate ranges
For pulsed signals, the transmission intervals should not be included in the statistical
evaluation. Thus, you must define gate ranges to be included in the measurement.
1. Press the MEAS CONFIG key, then select the "APD Config" or "CCDF Config"
softkey.
The "APD" or "CCDF" dialog box is displayed.
2. Select the "Edit Gate Ranges" button.
3. Define the time period for which the input signal is to be analyzed, for example the
duration of 3 signal pulses.
4. For each active trace, define up to three ranges within the time period to be mea-
sured. In the example covering 3 pulses, you could define one range for each
pulse.
a) Assuming the external trigger determines T=0 as the start of the first pulse,
define the start time of range 1 at 0
s.
Statistical Measurements (APD, CCDF)
