R&S ZVB - Page 509

R&S
®
ZVA / R&S
®
ZVB / R&S
®
ZVT GUI Reference
Channel Menu
Operating Manual 1145.1084.12 – 30 494
 PCal denotes an active power calibration with unchanged sweep points (no interpolation or
extrapolation).
 PCai denotes an active, interpolated power calibration (the calibration data for at least one sweep
point is interpolated).
 PCa? denotes an active power calibration with changed receiver settings (changed step
attenuator settings and disabled ALC) or with changed IF offsets (see Simultaneous Measurement
with Frequency Offset).
 PCao denotes an active power calibration with a changed source power (changed base power or
generator step attenuator settings).
 PCax denotes an active, extrapolated power calibration. The current stimulus range exceeds the
calibrated stimulus range. The power calibration data of the first calibrated sweep point is used for
all smaller stimulus values; the power calibration data of the last calibrated sweep point is used for
all larger stimulus values.
 Pcal Off indicates that the power calibration was deliberately switched off.
A lower label in the list has priority over the higher labels (e.g. if the power calibration is interpolated and
the source power is changed, then the label PCao is displayed).
The labels appear in the trace list, provided that the measurement result is an S-parameter, wave quantity,
ratio, or a derived quantity (stability factor, PAE), and that the effects of an inaccurate source or receiver
power have been consistently removed. The conditions for consistency depend on the measured quantity
(see also Data Flow):
 For S-parameters and quantities derived from S-parameters (stability factors), only the source
power calibration is relevant. S-parameters S
xy
represent the ratio of a received wave b
x
to a
driving wave a
y
, therefore the absolute receiver power levels are not critical. A PCal label
indicates a calibrated source power at all drive ports.
 For wave quantities and derived quantities (e.g. ratios, PAE), only the receiver power calibration is
relevant. Due to the linearity of the receiver, a modification of the base power or generator step
attenuator settings has no effect. A PCal label for a wave quantity indicates a calibrated receive
port. A PCal label for a ratio indicates that both receive ports are calibrated. Notice that wave
quantities and ratios are not system error corrected.
Remote control:
[SENSe<Ch>:]CORRection:PSTATe?
Noise Figure Calibration State Labels
The following labels in the noise figure trace line inform you about the status or type of the current noise
figure calibration.
Label
Meaning
NCal
A consistent set of power and noise figure calibration data is available at each sweep point. The calibration is applied.
NCai
The noise figure 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.
NCax
The noise figure calibration is applied, however, the current stimulus range exceeds the calibrated sweep range. The
calibration data is extrapolated.
NCa?
The noise figure calibration is applied, however, the accuracy is questionable e.g. because one of the following applies:
 Missing source or receiver power calibration data (steps 2 and 3 of the setup guide).
 The bandwidth or detector measurement time settings during the calibration differ from the settings during the