Getting Started
R&S
®
FSW
51
User Manual 1173.9411.02 ─ 19
The upper BNC connectors BASEBAND INPUT I and BASEBAND INPUT Q are used
to input single-ended signals, the positive signal input for differential signals, as well as
input from active Rohde
&
Schwarz probes (R&S RT-ZSxx and differential probes RT-
ZDxx).
The lower BNC connectors
Ī
and
Ǭ
are used to input the negative signal for differential
signals.
For complex signal input (I+jQ), always use two identical cables for the I and Q con-
nectors (same length, same type, same manufacturer). Otherwise, time delay or gain
imbalance may occur between the different cables, which cannot be calibrated.
All connectors have a fixed impedance of 50
Ω and may receive a maximum input level
of 4
V
pp
each.
Risk of instrument damage
Do not overload the BASEBAND INPUT connectors. An input voltage of 4
V must
never be exceeded. Noncompliance will destroy the Analog Baseband Interface com-
ponents.
The device that provides analog baseband input (or the probe) must be connected to
the R&S
FSW accordingly.
Since the Digital I/Q input and the Analog Baseband input use the same digital signal
path, both cannot be used simultaneously. When one is activated, established connec-
tions for the other are disconnected. When the second input is deactivated, connec-
tions to the first are re-established. This may cause a short delay in data transfer after
switching the input source.
Input via the Analog Baseband Interface can be enabled in the I/Q Analyzer, the Ana-
log Demodulation application, or in one of the optional applications that process I/Q
data (where available).
3.2.1.14
TRIGGER INPUT / OUTPUT
The female TRIGGER INPUT connector for external trigger or gate input is used to
control the measurement by means of an external signal. The voltage levels can range
from 0.5 to 3.5 V. The default value is 1.4 V. The typical input impedance is 10 kΩ.
The female BNC TRIGGER INPUT / OUTPUT connector can be used to receive a sec-
ond external signal or to provide a signal to another device. The signal is TTL compati-
ble (0 V / 5 V). You can control the connector usage in the "Trigger" settings (TRIG
key).
Instrument Tour
