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Concepts and Features
R&S
®
ZNB/ZNBT
207
User Manual 1173.9163.02 ─ 55
Time-Gated Frequency Domain Trace
The trace in the frequency domain depends on the state of the "Time Gate":
●
If the gate is disabled, the frequency domain (FD) trace corresponds to the mea-
sured sweep results before the time-domain transformation.
●
If the gate is enabled, the displayed frequency domain trace is calculated from the
time domain (TD) trace which is gated and transformed back into the frequency
domain.
The analyzer uses fixed "No Profiling (Rectangle)" window settings to transform the
measured trace into time domain. The TD trace is gated using the selected time gate.
The gated trace is transformed back into frequency domain using a "No Profiling (Rect-
angle)" window.
The shape, width and position of the time gate affect the gated frequency domain
trace. The window type selection in the "Define Transform" dialog is ignored. The
selected window is used again when the TD trace is displayed ("Time Domain: On").
The rectangular "No Profiling (Rectangle) "windows minimize numerical inaccuracies
near the boundaries of the measured frequency span. In the limit where the effect of
the time gate vanishes (e.g. a gate of type "Notch" and a very small width), the time
gated trace is equal to the original measured trace.
5.7.2.6
Time Domain S
VSWR
Measurements
The vector network analyzer R&S
ZNB/ZNBT with time domain option K2 supports TD
site VSWR measurements.
For the frequency range 1
GHz to 18
GHz, this method of S
VSWR
measurement is pro-
posed in standard ANSI
C63.25.
Hence an instrument with upper frequency limit above 18 GHz that is equipped with
time domain option K2 supports TD site VSWR measurements in accordance with
ANSI C63.25.
Optional Extensions and Accessories