Rohde & Schwarz SMW200A - Specifics of the Analog I;Q Interfaces

Signal Routing and System Configuration
R&S
®
SMW200A
137User Manual 1175.6632.02 ─ 16
3.3.4.2 Specifics of the Analog I/Q Interfaces
The R&S SMW outputs the digitally modulated signal not only directly but also conver-
ted to an analog I/Q baseband output signal. The R&S SMW outputs the analog base-
band signal single ended or differential (non-inverted); an RF envelope signal can be
generated, too.
Differential output signal
The differential output provides symmetrical signals for differential inputs of DUTs with-
out the need of additional external electric network. To achieve an optimal and bal-
anced operating point of these inputs, ensure the correct adjustment of the used DC
voltage ("Bias") and the offset ("Offset") between inverting and non-inverting output.
Refer to the descriptions Bias (EMF) and Offset (EMF) for a description of the effect of
these parameters.
Maximum overall output voltage
The voltage of the analog output signals is defined as a combination of output voltage
of the I and Q signal components and an optional bias voltage. If the differential output
is used, an additional offset can be set, too. The values of these parameters are inter-
dependent so that the magnitude of the sum of output voltage and bias voltage must
not exceed 4V.
The following applies:
●
Single ended signal:
V
p
+ V
bias
≤ 4 V
●
Differential signal:
0.5*V
p
+ |V
bias
| + 0.5*V
offset
≤ 4 V
Where:
●
V
p
is the output voltage as set with the parameter I/Q Level Vp EMF
●
V
bias
is the bias voltage as set with the parameter Bias (EMF)
●
V
offset
is the offset between inverting and non-inverting output as set with the
parameter Offset (EMF)
3.4 System Configuration Settings
The "System Configuration" dialog is the central point for the configuration of the signal
flow. The provided settings assist you to fulfill your configuration tasks, like changing
the selected MIMO mode or support you by connecting new devices to the baseband
outputs.
The settings in this dialog comprise the fading configuration, the baseband source con-
figuration, the mapping, and the processing of the generated I/Q streams. Form this
dialog, you can also control and configure the connections to instruments connected to
the RF and I/Q connectors.
System Configuration Settings