R&S
®
ZVA / R&S
®
ZVB / R&S
®
ZVT GUI Reference
Trace Menu
Operating Manual 1145.1084.12 – 30 140
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.
CALCulate<Chn>: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. 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 (reference phase = 0°). If φ (C) exceeds +180° 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:
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 displayed in the polar diagram. As an alternative to direct phase measurements, the
analyzer provides the derivative of the phase response for a frequency sweep (Delay).
CALCulate<Chn>:FORMat 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
11
, S
22
etc.), 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 application example.
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