Instrument Function
R&S
®
SMBV100A
248
Operating Manual 1407.6062.32 ─ 08
The crest factor gives the difference in level between the peak envelope power (PEP)
and average power value (RMS) in dB.
This value is necessary to allow the correct output power to be generated at the RF output.
When the set output power is generated, the R&S Signal Generator uses this value to
compensate the average power which is lower compared to the peak power.
The maximum input voltage at the I/Q input is equated to the peak power and is used as
the "reference" for setting the level of the output signal. Since the signal does not usually
supply the peak power at a constant level and instead supplies a lower average power,
the crest factor specifies how many dB have to be added internally so that the correct
output power is achieved.
SCPI command:
5.6 Impairment of Digital I/Q Signal and Noise Generator -
AWGN/IMP Block
The R&S SMBV allows the digital I/Q signal to be impaired before it is passed on to the
I/Q modulator, and also noise to be added to the signal. The noise generator can also be
used to generate a pure noise signal.
These settings are available in the block diagram in the "AWGN/IMP" function block as
well as in the menu with the same name which is opened using the MENU key.
The equipment options for the basic unit (R&S Signal Generator with frequency option
R&S SMBV-B10x) include the "Impairments" functionality and the option for noise gen-
eration R&S SMBV-K62 (Additive White Gaussian Noise) for "AWGN".
Selecting the menu item "I/Q Impairments (Digital Baseband)..." opens the I/Q impair-
ment settings dialog. This dialog covers the settings for I/Q impairment, like carrier leak-
age, imbalance and quadrature offset.
To access the AWGN settings, select "AWGN...". This dialog contains the settings of the
RFI signal generator, noise level configuration and CW interfering parameters.
Selecting the menu item "I/Q Out Settings" opens a dialog with the parameters for the I/
Q output signal.
The single ended or differential output is configured in the "I/Q Out Settings" dialog.
Impairment of Digital I/Q Signal and Noise Generator - AWGN/IMP Block
Summary of Contents for SMBV100A
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