Rohde & Schwarz FPL1000 Series, User Manual

Page: 258 / 899

The Spectrum Application (RF Measurements)
R&S
®
FPL1000
258 User Manual 1178.3370.02 ─ 03
Alternatively, the results can be output as channel power density, i.e. in reference to
the measurement bandwidth.
Furthermore, the measured power values of the displayed trace can be retrieved as
usual using the
TRAC:DATA?
commands (see
TRACe<n>[:DATA]
on page 703). In
this case, the measured power value for each sweep point (by default 1001) is
returned.
7.2.3.3 Channel Power Basics
Some background knowledge on basic terms and principles used in channel power
measurements is provided here for a better understanding of the required configuration
settings.
● Recommended Common Measurement Parameters ............................................258
Recommended Common Measurement Parameters
The following sections provide recommendations on the most important measurement
parameters for channel power measurements.
All instrument settings for the selected channel setup (channel bandwidth, channel
spacing) can be optimized automatically using the "Adjust Settings" function (see
"Opti-
mized Settings ( Adjust Settings )" on page 266).
The easiest way to configure a measurement is using the configuration "Overview" ,
see
Chapter 7.1, "Configuration Overview" , on page 230.
● Sweep Time ......................................................................................................... 258
● Frequency Span ....................................................................................................259
● Resolution Bandwidth (RBW) ................................................................................260
● Video Bandwidth (VBW) ........................................................................................260
● Detector .................................................................................................................261
● Trace Averaging ....................................................................................................261
● Reference Level ....................................................................................................261
Sweep Time
The "Sweep Time" is selected depending on the desired reproducibility of results.
Reproducibility increases with "Sweep Time" since power measurement is then per-
formed over a longer time period. As a general approach, approximately 500 non-cor-
related measured values are required for a reproducibility of 0.5
dB. (That means: 95
% of the measurements are within 0.5 dB of the true measured value). Approximately
5000 measured values are required for a reproducibility of 0.1 dB (99 %). These values
are valid for white noise. The measured values are considered as non-correlated if
their time interval corresponds to the reciprocal of the measured bandwidth.
The number of A/D converter values, N, used to calculate the power, is defined by the
"Sweep Time" . The time per trace pixel for power measurements is directly propor-
tional to the selected "Sweep Time" .
Measurements and Results