Rohde & Schwarz SMBV100B - (Baseband) Gain; Crest Factor; Optimization Mode

Applying I/Q Vector Modulation
R&S
®
SMBV100B
281User Manual 1178.4460.02 ─ 03
Crest Factor
If "Source = Analog Wideband I/Q Input", sets the crest factor of the externally supplied
analog signal.
The crest factor gives the difference in level between the peak envelope power (PEP)
and the average power value (RMS) in dB. The R&S SMBV100B uses this value for
the calculation of the RF output power. For more information, refer to "Important Signal
Parameters and Interface's Characteristics" on page 438
Note:
To set the crest factor of an externally supplied digital signal, use the parameter:
●
"BB Input > Input Level" > Crest Factor.
Remote command:
[:SOURce<hw>]:IQ:CREStfactor on page 831
Optimization Mode
Selects the optimization mode.
For information on the I/Q modulation performance in any of the modes, see the data
sheet.
"Fast"
Fast optimization by compensation for I/Q skew.
This mode suitable in time sensitive environments.
"High Quality"
With "Source > Internal Baseband", enables an optimization by com-
pensation for I/Q skew and frequency response correction.
This mode generates flat signal but requires longer setting time and
leads to signal interruption.
Note:
Do not use the mode "I/Q Modulator > Optimization Mode > High
Quality" in combination with the modes "RF Level > Setting Charac-
teristics > Uninterrupted/Strictly Monotone".
The high quality I/Q optimization leads to RF signal interruption. The
requirements of the RF level modes "Uninterrupted" and "Strictly
Monotone" can not be fulfilled.
Remote command:
[:SOURce<hw>]:BB:IMPairment:OPTimization:MODE on page 806
(Baseband) Gain
Optimizes the modulation of the I/Q modulator for a subset of measurement require-
ment. Provided is a dynamic range of 16 dB divided into 2 dB steps. The optimization
is a trade-off between signal distortion and signal-to-noise ratio (SNR).
See also Chapter 5.5, "How to Adjust the I/Q Modulator to Optimize Performance",
on page 284.
"-4 dB/- 2 dB (Low Distortion)"
Activates -4 dB or -2 dB gain.
Baseband signal is internally attenuated to minimize signal distor-
tions; the intermodulation characteristics of signal are optimized, the
SNR however decreases.
"0 dB"
No changes on the baseband signal; optimization is not applied.
I/Q Modulator Settings