VNA Concepts and Features
R&S
®
ZNL/ZNLE
281
User Manual 1178.5966.02 ─ 07
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.
8.7.2
Distance to Fault Measurements
Option R&S
ZNL-K3
With option K3 "Distance-to-Fault", the R&S
ZNL/ZNLE can locate faults and disconti-
nuities on cables and transmission lines.
Since fimware version 1.30, this option is also available for the R&S
ZNLE.
Faults produce peaks on the Impulse Response (in the time domain) that is calculated
from the measured reflection S-parameter trace via inverse Fourier transformation. The
distance between the reference plane and the fault can then be calculated from the
propagation time, accounting for the electrical properties of the transmission line.
Moreover it is possible to define which of the peaks should be considered as being due
to a fault.
The following example shows the reflection at the end of a faultless open cable con-
nected to test port 2. A full one-port calibration ensures that the distance is measured
from the test port position (reference plane = distance zero). The horizontal position of
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