Rohde & Schwarz R&S SMW200A - Overview of the Baseband and RF Output Signals

Signal Routing and System Configuration
R&S
®
SMW200A
118User Manual 1175.6632.02 ─ 30
Application examples of the externally supplied digital baseband signal
Provided the instrument is equipped with the required options, in particular with at least
two coder boards, the externally applied signals can be used for and further processed
as follows:
●
Used as a standalone baseband source and processed separately, e.g. faded,
detuned, or loaded with noise or directly applied to the I/Q modulator
●
Used as a user-specific wanted signal or interference signals to the internally gen-
erated signals
●
In Standard baseband, routed to one or to all the signal paths, added to the inter-
nally generated baseband signal possibly also frequency shifted
●
Used as a baseband source for digital signals in test setups requiring more than
four baseband signals (Tx antennas) or entities
Input interface for the external analog signal
The R&S SMW provides also an input interface for an external analog (wideband or
differential) I/Q signal; the external signal is fed directly to the I/Q modulator. For
description of the related connectors and settings, see Chapter 7, "Applying I/Q Vector
Modulation", on page 448 and Table 7-1.
4.3.3 Overview of the Baseband and RF Output Signals
Usually, the generated baseband signal is modulated on the RF frequency and output
at the RF connectors. For MIMO configurations with more than two Rx antennas, how-
ever, the two RF output signals are not sufficient. For MIMO configurations, for test set-
ups in which the R&S SMW acts as a baseband signal source or as a pure fading sim-
ulator, it provides also connectors to output the baseband signal. As shown in
Table 4-4, the R&S SMW outputs the digitally modulated signal directly or converted to
an analog I/Q baseband output signal. The analog baseband signal can be output sin-
gle ended or differential (non-inverted); an RF envelope signal can be generated, too.
The Table 4-4 shows the possible output connectors with the corresponding kind of sig-
nal. Which logical information, i.e. which stream, is output at which connector is
defined by the "I/Q Stream Mapper" (see Chapter 4.4.2, "I/Q Stream Mapper Settings",
on page 132).
Overview of the Input and Output Signals and Interfaces