Basics on I/Q Data Acquisition and Processing
R&S
®
FSV/A3000 I/Q
Analyzer
35
User Manual 1178.8536.02 ─ 01
Overloading
At a reference level of -10 dBm and at an external generator output level of the same
value, the R&S
FSV/A operates without overrange reserve. That means the
R&S
FSV/A is in danger of being overloaded if a signal is applied whose amplitude is
higher than the reference line. In this case, either the message "RF OVLD" for over-
load or "ADC OVLD" for exceeded display range (clipping of the trace at the upper dia-
gram border = overrange) is displayed in the status line.
Overloading can be avoided as follows:
●
Reducing the output level of the external generator (
in "External Generator > Measurement Configuration")
●
Increasing the reference level (
in the "Amplitude" menu)
4.4
Basics on Input from I/Q Data Files
The I/Q data to be evaluated in a particular R&S
FSV/A application can not only be
captured by the application itself, it can also be loaded from a file, provided it has the
correct format. The file is then used as the input source for the application.
For example, you can capture I/Q data using the I/Q Analyzer application, store it to a
file, and then analyze the signal parameters for that data later using the Pulse applica-
tion (if available).
The I/Q data must be stored in a format with the file extension
.iq.tar
. For a detailed
Chapter C, "I/Q Data File Format (iq-tar)"
An application note on converting Rohde
&
Schwarz I/Q data files is available from the
Rohde & Schwarz website:
1EF85: Converting R&S I/Q data files
For I/Q file input, the stored I/Q data remains available as input for any number of sub-
sequent measurements. When the data is used as an input source, the data acquisi-
tion settings in the current application (attenuation, center frequency, measurement
bandwidth, sample rate) can be ignored. As a result, these settings cannot be changed
in the current application. Only the measurement time can be decreased, in order to
perform measurements on an extract of the available data (from the beginning of the
file) only.
When using input from an I/Q data file, the [RUN SINGLE] function starts a single mea-
surement (i.e. analysis) of the stored I/Q data, while the [RUN CONT] function repeat-
edly analyzes the same data from the file.
Basics on Input from I/Q Data Files