R&S
®
ZVL
System Overview
Calibration Overview
Quick Start Guide 1303.6538.62-01
93
3.3 Calibration Overview
Calibration is the process of eliminating systematic, reproducible errors from the
measurement results (system error correction). The process involves the following
stages:
1. A set of calibration standards is selected and measured over the required sweep
range. For many calibration types the magnitude and phase response of each
calibration standard (i.e. its S-parameters if no system errors occur) must be
known within the entire sweep range.
2. The analyzer compares the measurement data of the standards with their known,
ideal response. The difference is used to calculate the system errors using a
particular error model (calibration type) and derive a set of system error correction
data.
3. The system error correction data is used to correct the measurement results of a
DUT that is measured instead of the standards.
Calibration is always channel-specific because it depends on the hardware settings, in
particular on the sweep range. The means that a system error correction data set is
stored with the calibrated channel.
The analyzer provides a wide range of sophisticated calibration methods for all types of
measurements. Which calibration method is selected depends on the expected system
errors, the accuracy requirements of the measurement, on the test setup and on the
types of calibration standards available.
Due to the analyzer's calibration wizard, calibration is a straightforward, menu-guided
process. Moreover, it is possible to perform the entire calibration process automatically
using a calibration unit (accessory R&S ZV-Z5x)
.
Storing system error correction data
The system error correction data determined in a calibration procedure is stored on
the analyzer. You can read this correction data using the remote control command
[SENSe<Ch>:]CORRection:CDATa.
You can also replace the correction data of
the analyzer by your own correction data sets.
A label
Cal Off !
appears behind the trace list if the system error correction no longer
applies to one or more traces:
This may happen for the one of the following reasons:
E
The sweep range is outside the calibrated frequency range.
E
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).
E
The system error correction has been switched off deliberately (Correction Off).
