VNA GUI Reference
R&S
®
ZNL/ZNLE
385
User Manual 1178.5966.02 ─ 07
|
|
1
|
|
1
ii
ii
S
S
SWR
The superposition of incident and reflected wave on the transmission line connecting
the analyzer and the DUT causes an interference pattern with variable envelope volt-
age. The SWR is the ratio of the maximum voltage to the minimum envelope voltage
along the line.
Interpretation of the SWR
The superposition of the incident wave I and the reflected wave R on the transmission
line connecting the analyzer and the DUT causes an interference pattern with variable
envelope voltage. The SWR is the ratio of the maximum voltage to the minimum enve-
lope voltage along the line:
SWR = V
Max
/V
Min
= (|V
I
| + |V
R
|) / (|V
I
| – |V
R
|) = (1 + |S
ii
|) / (1 – |S
ii
|)
Application:
Reflection measurements with conversion of the complex S-parameter to
a real SWR.
Remote command:
SWR
Unwr Phase
Selects a Cartesian diagram with an arbitrarily scaled linear vertical axis to display the
phase of the measured quantity.
Properties:
The stimulus variable appears on the horizontal axis, scaled linearly. The
phase of the complex quantity C, i.e. φ (C) = arctan ( Im(C) / Re(C) ), appears on the
vertical axis. φ (C) is measured relative to the phase at the start of the sweep (refer-
ence phase = 0°). In contrast to the normal Phase format, the display range is not limi-
ted to values between –180° and +180°. This format avoids artificial jumps of the trace
but can entail a relatively wide phase range if the sweep span is large.
Application:
Phase measurements, e.g. phase distortion, deviation from linearity.
Tip:
After changing to the "Unwr Phase" format, use the "Auto Scale Trace" function to
rescale the vertical axis and view the entire trace (see
Remote command:
SWR
Lin Mag
Selects a Cartesian diagram with a linear vertical axis scale to display the magnitude of
the measured quantity.
Properties:
The stimulus variable appears on the horizontal axis, scaled linearly. The
magnitude of the complex quantity C, i.e. |C| = sqrt ( Re(C)
2
+ Im(C)
2
), appears on the
vertical axis, also scaled linearly.
Application:
Real measurement data (i.e. the Stability Factors and the DC voltages)
are always displayed in a Lin Mag diagram.
Tip (alternative formats):
The magnitude of each complex quantity can be displayed
on a logarithmic scale. It is possible to view the real and imaginary parts instead of the
magnitude and phase.
Format Softtool
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Allice Messtechnik GmbH
