Measurements
R&S
®
FSW
145
User Manual 1173.9411.02 ─ 19
The RMS detector can be set for the defined channel settings automatically using the
"Adjust Settings" function in the "Ch Power" menu or the "General Settings" tab of the
"ACLR Setup" dialog box (see
"Optimized Settings (Adjust Settings)"
You can set the detector manually in the "Traces" configuration dialog box, see
Trace Averaging
Averaging, which is often performed to stabilize the measurement results, leads to a
level indication that is too low and should therefore be avoided. The reduction in the
displayed power depends on the number of averages and the signal characteristics in
the channel to be measured.
The "Adjust Settings" function switches off trace averaging. You can deactivate the
trace averaging manually in the "Traces" configuration dialog box, see
Reference Level
To achieve an optimum dynamic range, the reference level has to be set such that the
signal is as close to the reference level as possible without forcing an overload mes-
sage or limiting the dynamic range by an S/N ratio that is too small. Since the mea-
surement bandwidth for channel power measurements is significantly smaller than the
signal bandwidth, the signal path may be overloaded although the trace is still signifi-
cantly below the reference level.
The reference level is not influenced by the selection of a predefined standard or by
the automatic setting adjustment. The reference level can be set automatically using
the "Auto Level" function in the AUTO SET menu, or manually in the "Amplitude"
menu.
5.3.3.4
Measurement on Multi-Standard Radio (MSR) Signals
Modern base stations may contain multiple signals for different communication stand-
ards. A new measurement standard is provided for the R&S
FSW ACLR measurement
that allows you to measure such MSR signals, including non-contiguous setups. Multi-
ple (also non-)contiguous transmit channels can be specified at absolute frequencies,
independent from the common center frequency selected for display.
Signal structure
Up to 18 transmit channels can be grouped in a maximum of 5
sub blocks
. Between
two sub blocks, two gaps are defined: a
lower gap
and an
upper gap
. Each gap in turn
contains 2 channels. The channels in the upper gap are identical to those in the lower
gap, but inverted. To either side of the outermost transmit channels, lower and upper
adjacent channels can be defined as in common ACLR measurement setups.
Channel Power and Adjacent-Channel Power (ACLR) Measurement
