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

Signal Routing and System Configuration
R&S
®
SMW200A
133User Manual 1175.6632.02 ─ 16
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Used as a user-specific wanted signal or interference signals to the internally gen-
erated signals
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Routed to one or to all the signal paths, added to the internally generated base-
band signal possibly also frequency shifted
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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 6, "Applying I/Q Vector
Modulation", on page 415 and Table 6-1.
3.3.3 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 3-4, 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 3-4 shows the possible output connectors with the corresponding kind of
signal. Which logical information, i.e. which stream, is output at which connector is
defined by the "I/Q Stream Mapper" (see Chapter 3.4.2, "I/Q Stream Mapper Settings",
on page 144).
Table 3-4: Physical output signals
Type Output Signal Output connector GUI element Refer to
RF RF signal RF "RF" Chapter 7, "Configuring the Signal in the RF
Domain", on page 426
BB Digital signal BBMM 1/2
FAD 3/4/1/2
"I/Q Digital" Chapter 3.7, "I/Q Digital Output Settings",
on page 178
Analog signal
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Single ended
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Differential
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RF Envelope
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I/Q
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I/Q BAR
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I/I BAR
"I/Q Analog" Chapter 3.8, "I/Q Analog Output Settings",
on page 185
3.3.4 Important Signal Parameters and Interface's Characteristics
The correct signal processing of the externally supplied input signals in the instrument
and the correct processing of the output signal in the subsequently connected instru-
ment require information of some signal parameters, like sampling rate, crest factor
and signal level, expressed as peak or as RMS level value.
Overview of the Input and Output Signals and Interfaces