Rohde & Schwarz R&S SMW200A - How to Optimize the Carrier Leakage and Sidebands Suppression

Simulating Fading, Adding Noise and Predistortions, and Impairing the Signal
R&S
®
SMW200A
446User Manual 1175.6632.02 ─ 30
Remote command:
[:SOURce]:BB:IMPairment:BBMM<ch>:SKEW on page 1101
[:SOURce]:BB:IMPairment:FADer<ch>:SKEW on page 1101
[:SOURce]:BB:IMPairment:IQOutput<ch>:SKEW on page 1101
[:SOURce]:BB:IMPairment:RF<ch>:SKEW on page 1101
IQ Delay
In the "I/Q Modulator or I/Q Analog > Digital Impairments" dialog, sets the time delay of
both I and Q vectors relative to the selected trigger and marker.
A positive value means that the I and Q vectors delay relative to the marker/trigger and
the other way around.
If a R&S SGT is connected to one of the digital interfaces, digital impairments are
applied in the connected instrument (see Figure 4-17).
See also Chapter 10.3.1, "Connecting Multiple Instruments in Primary-Secondary
Instrument Mode", on page 640.
Remote command:
[:SOURce]:BB:IMPairment:BBMM<ch>:DELay on page 1099
[:SOURce]:BB:IMPairment:FADer<ch>:DELay on page 1099
[:SOURce]:BB:IMPairment:IQOutput<ch>:DELay on page 1099
[:SOURce]:BB:IMPairment:RF<ch>:DELay on page 1099
Phase Offset
Adds an additional phase offset after the stream mapper.
You can shift the phase at the different stages in the signal generation flow, see:
●
"Baseband Offsets" > Phase Offset.
●
"I/Q Stream Mapper" > Phase Offset.
Remote command:
[:SOURce]:BB:IMPairment:BBMM<ch>:POFFset on page 1102
[:SOURce]:BB:IMPairment:FADer<ch>:POFFset on page 1102
[:SOURce]:BB:IMPairment:IQOutput<ch>:POFFset on page 1102
[:SOURce]:BB:IMPairment:RF<ch>:POFFset on page 1102
6.4.4 How to Optimize the Carrier Leakage and Sidebands Suppression
Applying linear I/Q impairments helps to improve signal quality in the following cases:
●
To suppress a carrier leakage at the current RF frequency
●
To improve the attenuation of the unwanted sidebands
In the following examples, we assume that:
●
The R&S SMW generates a baseband signal
●
A spectrum analyzer is connected to the R&S SMW, the analyzed is configured,
and measures the required signal characteristics.
Impairing the Signal