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Applying I/Q Vector Modulation
R&S
®
SMBV100B
281
User 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
Parameters and Interface's Characteristics"
Note:
To set the crest factor of an
externally supplied digital signal
, use the parameter:
●
Remote command:
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
(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"
"-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