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Instrument Function
R&S
®
SMBV100A
324
Operating Manual 1176.8016.02 ─ 17
The equipment layout for generating the internal, digital modulation signals includes
the options Baseband Generator (B10) and/or one of the ARB only options (B51/K51x).
The ARB options feature different ARB memory sizes (see data sheet). Apart from the
memory size, however, the options offer the same functionality, either one can be
installed.
In addition, the appropriate option is required for the digital standards. These options
are specified in the description of the respective standard.
In the subsequent signal route the baseband signals can be frequency-shifted, detuned
or loaded with noise (see
Chapter 5.7, "Impairment of Digital I/Q Signal and Noise
5.9.1 Working with the Baseband Signal
Frequency and phase offset are defined at the topmost menu level in the "Baseband"
block or by using the MENU button under "Baseband".
The upper part of the "Baseband" dialog is used for selecting digital standards, digital
modulation and waveform generation. These menus are described in the respective
chapters relating to the modulation systems.
The lower part of the "Baseband" dialog can be used to define a frequency and phase
offset.
Frequency Offset
Enters the frequency offset for the baseband signal.
The frequency offset shifts the baseband frequency interval and provides a quick way
to shift the used frequency band in the RF frequency section without modifying the RF
settings.
Wenn a frequency offset is defined, an icon is displayed in the signal flow right to the
baseband block.
The complex I/Q bandwidth of the shifted useful signal must not exceed the total avail-
able baseband bandwidth (see data sheet). The setting range of the frequency offset is
then calculated as follow:
-(TotalBasebandBandwidth/2) + f
use
/2
≤
f
offset
≤
(TotalBasebandBandwidth/2) - f
use
/2 ,
where
f
use
is the complex useful bandwidth of the I/Q signal before the offset
f
offset
is the frequency offset
illustrates the setting range for the frequency offset.
Baseband Signal - Baseband Block