Concepts and Features
R&S
®
ZNC
15
User Manual 1173.9557.02 ─ 13
After changing the channel settings or selecting another measured quantity, the analyzer
needs some time to initialize the new sweep. This preparation period increases with the
number of points and the number of partial measurements involved. It is visualized by a
"Preparing Sweep" symbol in the status bar:
All analyzer settings can still be changed during sweep initialization. If necessary, the
analyzer terminates the current initialization and starts a new preparation period. During
the first sweep after a change of the channel settings, the asterisk symbol in the status
bar remains yellow:
The asterisk turns grey after the first sweep has been completed.
3.1.4.1
Partial Measurements and Driving Mode
Depending on the measurement task and the measured quantities, the measurement at
each sweep point can consist of one or several "partial measurements" with definite
hardware settings.
●
If a single S-parameter is measured (e.g. the reflection coefficient S
11
), the analyzer
can operate at fixed hardware settings. In particular, a fixed source port and receive
port is used. Each sweep point requires a single partial measurement.
See also
●
For a complete two-port S-parameter measurement (e.g. S
11
, S
21
, S
12
, S
22
) the ana-
lyzer needs to interchange the roles of the source and receive ports. Each sweep
point requires two partial measurements.
To enhance the accuracy, it is possible to insert a delay time before each partial mea-
surement.
In the default configuration, the R&S ZNC performs a partial measurement at all sweep
points (partial sweep) before the hardware settings are changed and the next partial
measurement is carried out in an additional sweep ("Alternated" driving mode). It is pos-
sible though to reverse the order of partial measurements and sweeps ("Chopped" mode;
see "CHANNEL > CHANNEL CONFIG > Mode > Driving Mode").
Advantages of alternated and chopped driving mode
If the settling time between adjacent frequency points is smaller than the settling time
between the partial measurements (which is generally true), then the "Alternated" mea-
surement is faster than a normal sweep so that a smaller sweep times can be set. On
the other hand, an "Alternated" measurement provides a result only during the last partial
sweep.
Basic Concepts