Monitoring Signal Characteristics
R&S
®
SMW200A
589User Manual 1175.6632.02 ─ 16
the power and peak power of the digital baseband signal at configurable acquisition
points, like at the input or the output of the fading block, the I/Q output connectors, etc.
The provided measurement results are based on signal measurement with different
acquisition methods.
The Chapter 8.2.2, "About Leveling", on page 589 provides general information on
leveling as well as a background information on the leveling principle used in the
instrument. Understanding of this principle a prerequisite for the correct interpretation
of the displayed measurement results.
Refer to Chapter 8.2.4, "How to Query Information on the Baseband Power Levels",
on page 597 for examples on using the baseband power measurements.
8.2.1 Required Options
The minimum equipment layout for using this function includes
●
Option Standard Baseband Generator (R&S SMW-B10) per signal path
●
Option Baseband main module, one/two I/Q paths to RF (R&S SMW-B13/-B13T)
8.2.2 About Leveling
The instrument provides different signal routing possibilities, involving also signal sum-
ming and enabling of power offsets.
This section does not focus on all possible alternatives but rather on the principle of
signal leveling. For detailed description refer to:
●
Chapter 3.2, "Possible Ways to Configure the Signal Flow", on page 126
●
Chapter 3.5, "Signal Routing Settings", on page 166
●
Chapter 3.2.2, "Using the System Configuration Capabilities", on page 127
●
Chapter 3.4.2, "I/Q Stream Mapper Settings", on page 144
●
Chapter 4.12, "Shifting and Boosting the Baseband Signal", on page 382
●
Chapter 5.2, "Adding Noise to the Signal", on page 389
Baseband Leveling Principle
In the R&S SMW, signal routing is performed in the digital domain, i.e. before the I/Q
modulation and the RF up-conversion. This implementation ensures a lossless signal
addition with high precision. In the digital domain however, real RF levels do not exist.
To let you define baseband signals with different average levels, the R&S SMW intro-
duces the concept of baseband leveling. This principle bases on a relative leveling of
the baseband signals in the digital domain.
By default, when two identical baseband signals are added, they are output at the RF
output with the equal average levels. To set a relative level between the baseband sig-
nals, use one of the possible alternatives, e.g:
●
Enable "Baseband > Baseband Offsets > Gain".
●
In MIMO configurations, select "Fading > Fading Settings" and adjust the MIMO
correlation matrix.
Querying Information on the Baseband Power Levels
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