VNA concepts and features
R&S
®
ZNL/ZNLE
203
User Manual 1178.5966.02 ─ 19
●
"Center" is calculated as the geometric or arithmetic mean of the lower band edge
frequency f
LBE
and the upper band edge frequency f
UBE
:
f
Center
= sqrt (f
LBE
* f
UBE
)
(geometric mean) or
f
Center
= 1/2 (f
LBE
+ f
UBE
)
(arithmetic mean)
The arithmetic mean is always higher than the geometric mean. The values are
close if the bandwidth is small compared to the geometric mean of the band edges.
●
"Lower Edge" is the closest frequency below the maximum (or minimum), where
the trace value is equal to the maximum (minimum) value minus (plus) n dB.
●
"Upper Edge" is the closest frequency above the maximum (or minimum), where
the trace value is equal to the maximum (minimum) value minus (plus) n dB.
●
The "Quality Factor (3 dB)" is the ratio between the "Center" frequency and the 3-
dB "Bandwidth"; it does not depend on the selected bandwidth factor.
●
The "Quality Factor (BW)" is the ratio between the "Center" frequency and the
"Bandwidth" displayed above. This result is available only if the selected bandwidth
factor is different from 3 dB.
●
"Loss" is the loss of the filter at its maximum (or minimum) and is equal to the
response value of marker no. 1. For an ideal bandpass filter, the loss is zero (0
dB), for an ideal bandstop filter it is –
∞
dB.
9.2.1.4
Channel list and channel settings
The main properties of all channels assigned to the traces in the diagram are displayed
in the channel list below the diagram.
Each line in the channel list describes a single channel. The channel of the active trace
is highlighted. The lines are divided into several sections with the following contents
(from left to right):
●
The "Channel Name" appears in the first section. The default names for new chan-
nels are Ch<n> with an automatically assigned number <n>. If a time domain
VNA screen elements
