Concepts and Features
R&S
®
ZNB/ZNBT
149
User Manual 1173.9163.02 ─ 53
Cal Off label
A label "Cal Off" appears in the trace line if the system error correction no longer
applies to the trace:
This can happen for one of the following reasons:
●
The sweep range is outside the calibrated frequency range.
●
The channel calibration is not sufficient for the measured quantity (e.g. a one-port
calibration has been performed, but the measured quantity is a transmission
parameter).
●
There is a mismatch between the current Frequency Offset settings and the Fre-
quency Offset settings that were used during calibration (see
●
There is a mismatch between the current sweep mode(s) and the sweep mode(s)
that were used during calibration (see
Chapter 5.1.4.4, "Stepped vs. Swept Mode"
●
The system error correction has been switched off deliberately ("User Cal Active" is
disabled).
The analyzer provides other labels to indicate the status of the current calibration; see
Chapter 5.5.4, "Calibration Labels"
Calibration and port de-/activation
The way the analyzer fimware activates/deactivates ports after a successfull calibration
(system error correction or power calibration) has slightly changed:
●
In all FW releases, calibrated ports that were previously disabled, are automatically
enabled as single-ended logical ports.
●
Starting with FW version 2.10, uncalibrated ports were disabled in the related
channel(s). If only one of the physical ports forming a balanced port was calibrated,
the balanced port was dissolved and only the uncalibrated (single-ended) port was
disabled.
In earlier FW versions there was no such port deactivation mechanism.
●
Since FW version 2.40 an uncalibrated port is only disabled if it is not used by a
measurement, i.e. if it is not required by any trace of the related channel.
5.5.1
Calibration Types
The analyzer provides a wide range of calibration types for one, two or more ports. The
calibration types differ in the number and types of standards used, the error terms, i.e.
the type of systematic errors corrected and the general accuracy. The following table
gives an overview.
Calibration
