System Overview
R&S
®
CMW500
69
User Manual 1173.9463.02 ─ 02
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Real-time or ARB generators can generate marker signals, to be used for synchro-
nization of a measurement; see
.
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Signaling applications provide trigger events which are synchronized to their downlink
(forward link) signals. Due to the known downlink/uplink timing of the mobile station
under test, a signaling trigger is generally appropriate for TX measurements run in
parallel. Some measurement results (e.g. the timing error) require a signaling trigger
as a timing reference.
Many measurements provide additional, specific trigger settings to improve their flexibility
and performance.
4.3.6.1
Marker Signals
A marker signal provides events at specific points in time that can be used to synchronize
the measurement. A typical example is a marker signal that is included in the waveform
files generated by R&S WinIQSIM 2.
Marker signals can be selected as trigger sources for measurements. The number and
type of available marker signals depends on the installed firmware applications. The R&S
CMW500 detects all available marker signals, depending on its hardware/software equip-
ment, and adds them to the list of available trigger sources.
4.3.6.2
Trigger Settings
Trigger settings enhance the flexibility of the trigger system and can help to avoid acci-
dental trigger events. The trigger settings depend on the selected trigger source. No
trigger settings apply to most "Free Run" measurements.
The following trigger settings are used in many firmware applications:
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The "Trigger Slope" setting specifies the edge (rising or falling edge) of the trigger
signal that is to provide the trigger event. This trigger parameter is appropriate for an
"IF Power" trigger source as well as for "External" trigger signals with TTL charac-
teristics. For some output trigger signals (e.g. the frame trigger of the "WiMAX Sig-
naling" application), the trigger slope parameter inverts the polarity of the frame trig-
ger signal.
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The "Trigger Threshold" defines the power of the trigger signal where the R&S
CMW500 generates a trigger event. Trigger signals below the trigger threshold are
ignored by the trigger system. This trigger parameter is used for "IF Power" trigger
source.
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A "Trigger Delay" delays the start of the measurement relative to the trigger event.
Typically, a trigger delay is used to compensate for known propagation delays in the
test setup or a known timing offset of the measured signal relative to the trigger signal.
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A "Trigger Timeout" is the maximum time after which an initiated measurement must
have received a trigger event. If no trigger event is received, a trigger timeout is indi-
cated in manual operation mode. In remote control mode the measurement is auto-
matically stopped. In "IF Power" trigger mode, a trigger timeout usually indicates that
the R&S CMW500 does not receive an RF input signal.
Measurements
