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Applying I/Q vector modulation
R&S
®
SMM100A
288
User Manual 1179.1341.02 ─ 05
To set the crest factor of an
externally supplied digital signal
, use the parameter:
●
Remote command:
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 6.5, "Optimizing I/Q modulation 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.
"+2 dB/ +4 dB/ + 6 dB/ + 8 dB (Low Noise)"
Activates a 2 dB, 4 dB, 6 dB or 8 dB gain
Baseband signal is internally boosted to maximize the SNR; signal
noise is minimized, the signal distortions however increase.
These values are suitable for 3GPP signals with high adjacent chan-
nel power ratio (ACPR).
Remote command:
For analog I/Q signal:
For digital I/Q signal:
Optimization Mode
Selects the optimization mode.
For information on the I/Q modulation performance in any of the modes, see the data
sheet.
Chapter 6.5, "Optimizing I/Q modulation performance"
See user manual R&S
SMM-K544 User-Defined Frequency Response Correction.
"Fast"
Fast optimization by compensation for I/Q skew.
This mode is suitable in time sensitive environments and for narrow-
band signals.
"High Quality Table"
This mode further improves the frequency response while maintaining
setting time. There is no signal interruption.
Select this mode if repeatable settings together with high-quality opti-
mization. Select it also, if wideband signals are required. The "High
Quality Table" mode is useful in the following cases:
●
If R&S SZU is connected to the R&S
SMM100A and the connec-
tion is active
I/Q modulator settings