R&S 1129.7246.03, Operating Manual

Page: 358 / 855

Operating Manual 1302.6163.12 - 03 4.327
R&S ESU Instrument Functions
Tracking Generator – Option R&S FSU-B9
4.10.3.1 Calibration of Reflection Measurement
The calibration mechanism for reflection measurement is basically the same as the
one used for transmission measurement.
CAL REFL
SHORT
The CAL REFL SHORT softkey starts the short-circuit calibration.
If both calibrations (open circuit, short circuit) are carried out, the calibration curve is
calculated by averaging the two measurements and stored in the memory. The order
of the two calibration measurements is free.
After the calibration the following message is displayed:
The message is cleared after approx. 3 seconds.
Remote command:
CORR:METH REFL
CORR:COLL THR
CAL REFL
OPEN
The CAL REFL OPEN softkey starts the open-circuit calibration. During calibration
the following message is displayed:
Remote command:
CORR:METH REFL
CORR:COLL OPEN
4.10.4 Calibration Mechanism
Calibration means a calculation of the difference between the currently measured
power and a reference curve, independent of the selected type of measurement
(transmission/reflection). The hardware settings used for measuring the reference
curve are included in the reference data set.
Even with normalization switched on, the device settings can be changed in a wide
area without stopping the normalization. This reduces the necessity to carry out a
new normalization to a minimum.
For this purpose the reference dataset (trace with 625 measured values) is stored
internally as a table of 625 points (frequency/level).
Differences in level settings between the reference curve and the current device set-
tings are taken into account automatically. If the span is reduced, a linear interpola-
tion of the intermediate values is applied. If the span increases, the values at the left
or right border of the reference data set are extrapolated to the current start or stop
frequency, i.e. the reference data set is extended by constant values.
An enhancement label is used to mark the different levels of measurement accu-
racy. This enhancement label is displayed at the right diagram border when normal-
ization is switched on and a deviation from the reference setting occurs. Three
accuracy levels are defined: