VNA GUI reference
R&S
®
ZNL/ZNLE
417
User Manual 1178.5966.02 ─ 19
Phase
Selects a Cartesian diagram with a linear vertical axis to display the phase of a com-
plex measured quantity in the range between –180 degrees and +180 degrees.
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°). If φ (C) e180° the curve jumps by –360°; if it falls below –
180°, the trace jumps by +360°. The result is a trace with a typical sawtooth shape.
The alternative "Unwr Phase" format avoids this behavior.
Application:
Phase measurements, e.g. phase distortion, deviation from linearity.
Tip (alternative formats):
The magnitude of each complex quantity can be displayed
on a linear scale or on a logarithmic scale. It is possible to view the real and imaginary
parts instead of the magnitude and phase. Both the magnitude and phase are dis-
played in the polar diagram. As an alternative to direct phase measurements, the ana-
lyzer provides the derivative of the phase response for a frequency sweep (
Remote command:
PHASe
Smith
Selects a Smith chart to display a complex quantity, primarily a reflection S-parameter.
Properties:
The Smith chart is a circular diagram obtained by mapping the positive
complex semi-plane into a unit circle. Points with the same resistance are located on
circles, points with the same reactance produce arcs. If the measured quantity is a
complex reflection coefficient S
ii
, then the unit Smith chart represents the normalized
impedance. In contrast to the polar diagram, the scaling of the diagram is not linear.
Application:
Reflection measurements; see example in
Tip:
The axis for the sweep variable is lost in Smith charts but the marker functions
easily provide the stimulus value of any measurement point. dB values for the magni-
tude and other conversions can be obtained by the "Marker Format" functions.
Remote command:
SMITh
Polar
Selects a polar diagram to display a complex quantity, primarily an S-parameter or
ratio.
Properties:
The polar diagram shows the measured data (response values) in the
complex plane with a horizontal real axis and a vertical imaginary axis. The magnitude
of a complex value is determined by its distance from the center, its phase is given by
the angle from the positive horizontal axis. In contrast to the Smith chart, the scaling of
the axes is linear.
Application:
Reflection or transmission measurements, see example in
Tip:
The axis for the sweep variable is lost in polar diagrams but the marker functions
easily provide the stimulus value of any measurement point. dB values for the magni-
tude and other conversions can be obtained by the "Marker Format" functions.
Format softtool
