R&S
®
ZVA / R&S
®
ZVB / R&S
®
ZVT GUI Reference
Trace Menu
Operating Manual 1145.1084.12 – 30 141
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.
CALCulate<Chn>:FORMat 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 application example.
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 magnitude and other conversions can be
obtained by means of the Marker Format functions.
CALCulate<Chn>:FORMat POLar
Delay
Calculates the (group) delay from the measured quantity (primarily: from a transmission S-parameter) and
displays it in a Cartesian diagram.
Properties: The group delay τ
g
represents the propagation time of wave through a device. τ
g
is a real
quantity and is calculated as the negative of the derivative of its phase response. A non-dispersive DUT
shows a linear phase response, which produces a constant delay (a constant ratio of phase difference to
frequency difference).
Mathematical relations: Delay, Aperture, Electrical Length
The group delay is defined as:
where
Φ
rad/deg
= Phase response in radians or degrees
ω = Frequency/angular velocity in radians/s
f = Frequency in Hz
In practice, the analyzer calculates an approximation to the derivative of the phase response, taking a
small frequency interval Δf and determining the corresponding phase change ΔΦ. The delay is thus
computed as:
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