Rohde & Schwarz 1145.1010.04/05/06, Operating Manual

Page: 197 / 813

R&S
®
ZVA/ZVB/ZVT Trace Menu
1145.1084.12 4.35 E-6
•
Imag selects a Cartesian diagram to display the imaginary part of a complex measured
quantity.
•
Inverted Smith selects an inverted Smith diagram to display an S-parameter or ratio.
•
Unwrapped Phase selects a Cartesian diagram with a linear vertical axis to display the phase of
the measured quantity in an arbitrary phase range.
The Format settings are closely related to the settings in the Scale submenu and in the Display menu.
All of them have an influence on the way the analyzer presents data on the screen.
The analyzer allows arbitrary combinations of display formats and measured quantities (Trace –
Measure). Nevertheless, in order to extract useful information from the data, it is important to
select a display format which is appropriate to the analysis of a particular measured quantity;
see Measured Quantities and Display Formats.
An extended range of formats is available for markers. To convert any point on a trace, create a
marker and select the appropriate marker format. Marker and trace formats can be applied
independently.
dB Mag
Selects a Cartesian diagram with a logarithmic scale of the vertical axis to display the magnitude of the
complex 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, scaled in dB. The
decibel conversion is calculated according to dB Mag(C) = 20 * log(|C|) dB.
Application: dB Mag is the default format for the complex, dimensionless S-parameters. The dB-scale
is the natural scale for measurements related to power ratios (insertion loss, gain etc.).
Alternative Formats
The magnitude of each complex quantity can be displayed on a linear scale. It is possible to view the
real and imaginary parts instead of the magnitude and phase. Both the magnitude and phase are
displayed in the polar diagram.
Remote control: CALCulate<Ch->Tr>:FORMat MLOGarithmic
Phase
Selects a Cartesian diagram with a linear vertical axis to display the phase of a complex 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. (C) = arctan ( Im(C) / Re(C) ), appears on the vertical axis. (C) is measured
relative to the phase at the start of the sweep (reference phase = 0°). If (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
Phase Unwrapped format avoids this behavior.
Application: Phase measurements, e.g. phase distortion, deviation from linearity.
Alternative Formats: