R&S FSH
Network Analyzer Mode
Calibrating Measurements
Operating Manual 1173.6275.12 - 30
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6.2 Calibrating Measurements
In its default state, the R&S FSH uses factory calibration. Factory calibration is a full 2-
port calibration over the current frequency range (i.e. span) of the R&S FSH. When
factory calibration is active, the status line reads
. In many cases, this calibration
already provides accurate results.
To get the best and most accurate results, however, you have to calibrate the
measurement manually, because factory calibration does not take the actual test setup
into account (e.g. cables). The R&S FSH provides several calibration methods. You
will need one of the available calibration standards R&S FSH-Z28, -Z29 (order no.
1300.7804.03 and 1300.7504.03) or R&S ZV-Z121 (order no. 1164.0496.02/.03).
Alternatively, you can create customized calibration kits with the functionality of the
R&S FSH4View software package and transfer those to the R&S FSH.
Before you calibrate the R&S FSH for the current measurement, you should set the
frequency parameters, reference level and attenuation levels. If you change one of
these parameters after a successful calibration, it may become invalid.
To successfully calibrate the test setup, you have to connect the calibration standard at
the reference plane, usually the output of the RF measurement cable.
During calibration, the R&S FSH removes systematic errors from the measurement.
This process is based on correction data it gets while performing the calibration.
The correction data for transmission measurements is based on the results of
comparing the transmission characteristics of the test setup to the frequency response
of the tracking generator. The correction data for reflection measurements is based on
the results of a reflection measurement at a short and an open on the bridge.
Calibration remains valid after turning off the R&S FSH or changing into another
operating mode as calibration data is saved in the internal memory of the R&S FSH. If
you save the measurement in a dataset, calibration data is part of that dataset. When
you restore the dataset and perform the same measurement again, you do not have to
recalibrate the R&S FSH.
6.2.1.1 Calibration States
The R&S FSH features several calibration states. It displays the current state in the
status line. The possible states depend on the calibration type (see below).
● (fcal)
The R&S FSH uses factory calibration. Factory calibration is restored after a preset
or self alignment. The R&S FSH also uses factory calibration if you change a
frequency parameter (span, start, stop or center frequency) to a value outside the
calibrated frequency range or if you measure another s-parameter than the one the
R&S FSH is calibrated for.
The calibration data for the factory calibration is already in the memory of the
R&S FSH when it is delivered. The factory calibration is a full two-port calibration.
