VNA concepts and features
R&S
®
ZNL/ZNLE
208
User Manual 1178.5966.02 ─ 19
The VNA firmware allows arbitrary combinations of trace formats and measured quan-
tities. However, to extract useful information from the measured data, it is important to
select a trace format which is appropriate for the analysis of a particular measured
quantity; see
Chapter 9.2.3.3, "Measured quantities and trace formats"
9.2.3.1
Cartesian trace formats
Cartesian trace formats assign a scalar response to the stimulus value, which can be
frequency, power (R&S
ZNL only), or time. The response can be calculated from the
measured quantity at the related stimulus value, but it can also be the result of some
mathematical transformation of the original (unformatted) trace.
Diagram representation
When a Cartesian trace is assigned to a diagram, the stimulus variable appears on the
horizontal axis (x-axis), the response values appear on the vertical axis (y-axis).
Graph Scaling
●
Except for the "Log Mag" format, the y-axis scale is always linear.
●
The x-axis scaling depends on the sweep type of the channel to which the trace is
assigned:
–
For sweep types "Lin Freq", "Power" (R&S
ZNL only), "CW Mode" and "Time" it
is scaled linearly.
–
For sweep type "Log Freq", it is scaled logarithmically.
The resulting linear or lin-log grid is plotted with the formatted trace.
The following examples show "dB Mag" Cartesian traces for the same measured quan-
tity and sweep range, but with "Lin Freq" and "Log Freq" sweep types.
Figure 9-2: S11 trace in dB Mag format: sweep type Lin Freq (top) and Log Freq (bottom)
VNA screen elements
