Rohde & Schwarz SMBV100A - Description of Individual Diagram Blocks of the Baseband Section

Getting Started
R&S
®
SMBV100A
53Operating Manual 1407.6062.32 ─ 08
Special features...
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Option R&S SMBV-K18 is a combined interface, i.e. it operates one direction at a
time.
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The R&S SMBV processes either the internally generated baseband signal, or the
signal supplied externally. Therefore, the baseband signal generator is turned off with
"BB In", and vice versa.
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If the baseband section and the RF section are decoupled, e.g. with output of the
digital I/Q signal, or if an external anaolg signal is fed to the I/Q modulator, both
sections can be processed independently.
Further processing of the I/Q signal
The R&S SMBV allows further processing of the I/Q signal, as summarized below:
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In the "AWGN/IMP" block, the R&S SMBV allows the digital I/Q signal to be impaired
or added with noise before it is passed on.
Additionally, a pure noise signal can be used and forwarded. In this case, the I/Q
baseband signal is disabled, indicated by the interrupted signal flow in the diagram.
●
If digital I/Q output is on, the R&S SMBV routes the signal, or the pure noise, directly
to the digital interface.
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If digital I/Q output is off, the instrument converts the signal to an analog I/Q signal
and routes it to the analog I/Q output and to the I/Q modulator of the RF path. Pure
noise is also provided at the analog outputs or can be forwarded to the I/Q modulator.
Additional White Gaussian Noise (option R&S SMBV-K62)
Additive white noise, which may be required for instance for measurements on mobile
radio base stations, can be produced with the AWGN software option (R&S SMBV-K62).
3.2.1 Description of Individual Diagram Blocks of the Baseband Section
Each function block can be activated or deactivated with the "ON" check box (on/off tog-
gling).
The ON/OFF TOGGLE key at the front panel (see "TOGGLE" on page 22) switches the
currently selected block on or off.
A detailed description of the blocks is provided below.
Baseband A block
In this block, the (first) baseband source is configured and activated. The block is dis-
played only if a baseband generator is available in the instrument.
Depending on the installed software options, various digital standards, user-configured
digital real time modulation or the built-in waveform generator (ARB) can be selected.
The selected modulation is displayed in the block.
Baseband Section