VNA GUI Reference
R&S
®
ZNL/ZNLE
347
User Manual 1178.5966.02 ─ 07
9.6.7.2
Available Cable Types... Dialog
The "Available Cable Types..." allows to display predefined and user-defined cable
types and to add/modify/delete user-defined cable types.
Among the predefined cable types there is an ideal air line (with a relative permittivity
of 1, a corresponding velocity factor of 1, and zero attenuation) and a wide range of
standard cable types.
Cable types are defined by their relative permittivity
εr
or, equivalently, by their velocity
factor
1/sqrt(εr)
, and a frequency dependent attenuation table (see
The velocity factor is a measure for the velocity of an electromagnetic wave in a dielec-
tric with permittivity ε
r
, relative to its velocity in a vacuum (velocity factor < 1). It is nee-
ded to convert the propagation times into distances.
Frequency Dependent Attenuation Table
The "Attenuation of <Cable Type>" dialog defines the frequency dependence of the
cable attenuation. The measured cables are assumed to be homogenuous so that the
attenuation per length unit is constant. This means that the attenuation can be
expressed in units of dB/m. Due to the skin effect and various other factors, the attenu-
ation is generally frequency-dependent.
For predefined cables, the table is read-only.
Access:
Available Cable Types... Dialog
> "Attenuation" column >
...
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