Concepts and features
R&S
®
ZNA
226
User Manual 1178.6462.02 ─ 20
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.
4.7.2.6
Time domain S
VSWR
measurements
The vector network analyzer R&S
ZNA 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 a R&S
ZNA equipped with time domain option K2 supports TD site VSWR mea-
surements in accordance with ANSI C63.25.
EMC Test Site Validation
EMC test sites for radiated emission measurements rely on free-space conditions to
minimize the influence of reflections on the received signal. Practically, near free-space
conditions are achieved by shielded enclosures fully lined with RF absorbing material.
Site validation
determines deviations from free-space conditions that must meet the
acceptance criterion for making EMC compliance measurements in a FAR (= fully
anechoic room). It is performed by measuring the
site voltage standing-wave ratio
(S
VSWR
), which is the ratio of maximum received signal to minimum received signal,
caused by interference between direct (intended) and reflected signals.
Optional extensions and accessories
