Setting and Using the Measurement Functions R&S FSH3
The transmission calibration remains valid until the center frequency or the span is changed on the
R&S FSH3. Track Gen Uncal is displayed in the top right-hand corner of the screen when calibration
is no longer valid.
If the reference is changed after calibration, greater measurement uncertainty must be anticipated. The
R&S FSH3 retains the calibration data but displays a red dot before Transmission in the top right-hand
corner of the screen to indicate a possible increase in measurement uncertainty (< 0.3 dB).
Changing any other of the parameters like bandwidth, detector, sweep time or measurement range has
no effect on measurement accuracy. This means they can be changed after calibration without any
reduction in accuracy.
When a data set for scalar transmission measurement is stored with calibration performed, the
calibration data can be stored along with the other settings (see Chapter 2, section "Saving Calibration
Data"). When such a data set is recalled, measurements can be performed without prior calibration,
providing the instrument's temperature does not deviate more than 5 °C from its temperature when the
data set was stored.
If the temperature deviation is greater, the R&S FSH3 outputs a (red) dot in front of • Transmission . A
precise measurement can then only be made after a calibration.
Vector measurement of transfer function
(only with option R&S FSH-K2)
With vector measurements, the R&S FSH3 analyzes both magnitude and phase of the receive signal,
thus correcting the influence it has on the measurement result by means of the complex correction
values obtained from the calibration routines with correct phase. Reference is made to the calibration
standards used (through connection and 50 Ω termination).
Compared to scalar measurement, the vector measurement of the transfer function yields higher
measurement accuracy and dynamic range.
¾ Press the MEAS key.
¾ Press the TRANSM VECT CAL softkey.
To calibrate the transfer measurement, the R&S FSH3
requests that the RF input be connected to the
tracking generator output.
¾ Connect the RF input of the R&S FSH3 directly to
the tracking generator output without the DUT.
¾ Press the F1 or F2 (CONTINUE) softkey to start
calibration.
¾ By pressing the F4 or F5 (CANCEL) softkey,
calibration can be aborted.
During calibration, the R&S FSH3 outputs the
message "Calibrating THROUGH, please wait...".
Calibration can be aborted with CANCEL.
1145.5973.12 4.58 E-6
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