Concepts and Features
R&S
®
ZNC
89
User Manual 1173.9557.02 ─ 13
Calibration procedure
The measurement receiver calibration is based on a received wave b
n
with known power.
The calibration involves a connection to a (previously source power-calibrated) source
port.
The received wave to calibrate is generated by the other analyzer port P
m
(m
≠
n). Alter-
natively, it is possible to connect an Open or Short standard to port P
n
: The measurement
receiver is calibrated using the reflected wave a
n
.
The measurement receiver calibration involves a single calibration sweep. The calibration
sweep is performed with current channel settings but with a maximum IF bandwidth of
10 kHz. Smaller IF bandwidths are maintained during the calibration sweep; larger band-
widths are restored after the sweep. The analyzer measures the power at each sweep
point, compares the result with the nominal power of the source, and compiles a correc-
tion table.
An acoustic signal indicates the end of the calibration sweep. At the same time, a check-
mark symbol next to the calibrated source indicates the status of the measurement
receiver calibration. After a change of the sweep points or sweep range, the analyzer
interpolates or extrapolates the calibration data.
3.5.6.3
Power Calibration Labels
Power calibration labels in the trace list for wave quantities and ratios inform you about
the status and type of the current scalar power calibration. The labels appear in the fol-
lowing instances:
●
For a-waves, if a source power calibration is available.
●
For b-waves, if a measurement receiver power calibration is available.
●
For ratios between a- and b-waves, if both a source power and a measurement
receiver power calibration is available.
Calibration of S-parameters
S-parameters and derived quantities (e.g. impedances, admittances, stability factors) are
assumed to be linear.
Therefore, a scalar power calibration is not applied to S-parameters and derived quanti-
ties; no power calibration labels appear in the trace list.
Table 3-8: Power calibration labels
Label
Meaning
PCal
A scalar power calibration is available and applied without interpolation or extrapolation
(see below).
This means that a set of measured correction data is available at each sweep point.
PCai
The power calibration is applied, however, the correction data for at least one sweep
point is interpolated from the measured values. This means that the channel settings
have been changed so that a current sweep point is different from the calibrated sweep
points. It is not possible to disable interpolation.
Calibration