Simulating Fading, Adding Noise and Predistortions, and Impairing the Signal
R&S
®
SMW200A
406User Manual 1175.6632.02 ─ 16
b) Select "Target CW Frequency Offset = 10 MHz"
c) Select "Noise Power/Output Results > Reference Mode = Noise"
d) Select "Interferer Power = -52 dB"
e) Select "AWGN > General > State > On".
3. Select "RF > State > On"
5.3 Impairing the Signal
In the R&S SMW, analog and digital linear impairments such as I/Q imbalance and
quadrature error can be added to the generated signal.
The instrument can also simulate the effect of non-linear memoryless effects like
AM/AM and AM/PM conversion.
See user manual R&S
®
SMW-K540, R&S
®
SMW-K541 Envelope Tracking and AM/AM,
AM/PM Predistortion.
5.3.1 Required Options
The equipment layout for signal impairments includes:
●
Option Standard or Wideband Baseband Generator (R&S SMW-B10/-B9) per sig-
nal path
●
Option Baseband main module, one/two I/Q paths to RF (R&S SMW-B13/-B13T) or
option Wideband baseband main module two I/Q paths to RF (R&S SMW-B13XT)
Sufficient for impairment of the digital I/Q and the analog signal
5.3.2 About the Linear I/Q Impairments
Signal impairments (I/Q Impairments) are well-defined arithmetic modifications of the
data. Every data sample is modified in the same way.
Adding linear impairments to the data stream is provided for the following purpose:
●
To simulate frequent sources of distortions in a real signal-processing chain as, it is
required for tests with dirty transmitter conditions (receiver tests)
●
To compensate the faults of the I/Q demodulator in the receiver
See Chapter 5.3.4, "How to Optimize the Carrier Leakage and Sidebands Suppres-
sion", on page 413.
The R&S SMW offers functions to impair the internally generated signal or the exter-
nally fed analog I/Q signal linearly:
●
Each generated I/Q stream can be impaired digitally
●
Analog impairments can be added to the externally applied analog I/Q signal,
before it is passed to in the I/Q modulator (see "Defining the input signal of the I/Q
modulator" on page 415)
Impairing the Signal
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