Rohde & Schwarz ZVL series, Operating Manual

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R&S ZVL GUI Reference
Channel Menu
Operating Manual 1303.6580.32-06
249
The offset parameters depend on whether or not the circuit model is defined in
Agilent Mode
(see
Add/Modify Calibration Kit
dialog):
• If
Agilent Mode
is active, then the standard is characterized by its
Delay
(in s), its characteristic
impedance
Z
0
(in
V
) and its
Offset Loss
(in G
V
/s).
• If
Agilent Mode
is switched off, then the standard is characterized by the ZVR-compatible
parameters
Electrical Length
(in m or foot (ft), depending on the
Distance Unit
selected in the
System Configuration
dialog), its
Char. Impedance
(in
V
) and its
Loss
(in dB/sqrt(GHz)). The loss
is zero and not editable as long as the electrical length is zero.
Both parameter sets are closely related. The
Electrical Length
is proportional to the
Delay
;
Z
0
corresponds
to the
Char. Impedance.
Moreover the analyzer converts an Agilent-type
Offset Loss
into a ZVR-type
Loss
and vice versa using the
Relative Permittivity
N
r
for the connector type defined in the
Offset Model...
dialog.
Offset parameters
The offset parameters have the following physical meaning:
•
The
Delay
is the propagation time of a wave traveling through the standard. The
Electrical Length
is equal to the
Delay
times the speed of light in the vacuum and is a measure for the length of
transmission line between the standard and the actual calibration plane. For a waveguide with
permittivity
N
r
and mechanical length L
mech
the following relations hold:
The default delay is 0 s, the default step width is 1 ns, corresponding to a step width of 299.792 mm
for the electrical length. The relations hold for one-port and 2-port standards.
•
Z
0
is the
Characteristic Impedance
of thestandard. If the standard is terminated with Z
0
, then its
input impedance is also equal to Z
0
.
Z
0
is not necessarily equal to the reference impedance of the
system (depending on the
Connector Type)
or the terminal impedance of the standard. The
characteristic impedance of the standard is only used in the context of calibration.
The default characteristic impedance is equal to the reference impedance of the system.
• The
Loss
is the energy loss along the transmission line due to the skin effect. For resistive lines
and at RF frequencies the loss is approximately proportional to the square root of the frequency.
In Agilent mode the
Offset Loss
is expressed in units of
V
/s at a frequency of 1 GHz. The following
formula holds:
To determine an offset loss value experimentally, measure the delay in seconds and the loss in dB
at 1 GHz and use the formula above.
The default
Loss
or
Offset Loss
is zero.