Concepts and features
R&S
®
ZNB/ZNBT
91
User Manual 1173.9163.02 ─ 62
After changing the channel settings or selecting another measured quantity, the ana-
lyzer 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 indica-
ted 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 analyzer displays an
asterisk symbol in the status bar.
4.1.4.1
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 ana-
lyzer 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
analyzer needs to interchange the roles of the source and receive ports. Each
sweep point requires two partial measurements.
To improve the accuracy, it is possible to insert a delay time before each partial mea-
surement.
In the default
"Alternated"
driving mode, the R&S
ZNB/ZNBT performs a partial mea-
surement at all sweep points (partial sweep) before the hardware settings are
changed. The next partial measurement is carried out in an additional sweep. In the
"Chopped"
driving mode, the order is reversed, i.e. the measurement proceeds sweep
point per sweep point, with varying hardware settings.
See Channel – [Channel
Config] > "Mode" > "Driving Mode".
Advantages of alternated and chopped driving mode
If the settling time between sweep points is smaller than the settling time between
hardware settings (which is generally true), then the "Alternated" mode is faster than
the "Chopped" mode. On the other hand, the "Chopped" mode builds up traces sweep
point per sweep point, whereas in the "Alternated" mode you have to wait for the last
partial sweep.
Basic concepts
