R&S ZVL
GUI Reference
Trace Menu
Operating Manual 1303.6580.32-06
198
imaginary parts are displayed in the polar diagram.
Remote control:
CALCulate<Chn>:FORMat IMAGinary
Inv Smith
S
elects an inverted Smith chart to display a complex quantity, primarily a reflection S-parameter.
Properties:
The Inverted Smith chart is a circular diagram obtained by mapping the positive complex
semi-plane into a unit circle. If the measured quantity is a complex reflection coefficient (S
11
, S
22
etc.), then
the unit Inverted Smith chart represents the normalized admittance. In contrast to the polar diagram, the
scaling of the diagram is not linear.
Application:
Reflection measurements, see application example.
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 magnitude and other conversions can be
obtained by means of the
Marker Format
functions.
Remote control:
CALCulate<Chn>:FORMat ISMith
Unwrapped Phase
S
elects 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.
X
(C) = arctan ( Im(C) / Re(C) ), appears on the vertical axis.
X
(C) is measured
relative to the phase at the start of the sweep (reference phase = 0°). In contrast to the normal Phase
format, the display range is not limited to values between –180° and +180°. This 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.
After changing to the
Unwrapped Phase
format, use
Trace – Scale – Autoscale
to re-scale the vertical
axis and view the entire trace.
Remote control:
CALCulate<Chn>:FORMat UPHase
Scale
The
Scale
settings
define how the current trace is presented in the diagram selected in the
Format
submenu.
