Setting and Using the Measurement Functions R&S FSH3
When calibration is over, the R&S FSH3 displays
DTF CAL in the top right-hand corner of the screen.
The REFLECT CAL softkey label is highlighted in
green to indicate that calibration has been successfully
completed.
The trace displays cable reflections versus distance
from the measurement plane.
Note: Calibration is performed over the entire R&S FSH3 frequency range. This eliminates the
need for recalibration when a different cable length is selected. The calibration data are
saved in the R&S FSH3's internal memory so that calibration remains effective when
switchover is made to another operating mode or the instrument is switched off. As a
precondition for calibration to remain valid, however, the instrument temperature must not
change by more than 5 °C after calibration. If the temperature changes by more than 5 °C,
a red circle is placed ahead of DTF CAL to indicate that there is a risk of increased
measurement error. In such a case, it is advisable to recalibrate the test setup.
¾ Unscrew the SHORT from the measurement cable.
¾ Screw the cable under test to the measurement cable.
The R&S FSH3 displays the reflections produced in
the cable under test. The measurement diagram on the
right shows a cable that is approximately 15 m long
and fitted with a connector 5 m from the start. The end
of the cable is terminated with a 3 dB attenuator pad.
The R&S FSH3 shows that the return loss of the
reflection from the termination at the end of the cable
(approx. 157 m) is approx. 7 dB. The connector, for
example, is the 20 dB peak at 5 m. On the extreme left
of the trace, the matching of the connection to the
cable under test can be seen.
1145.5973.12 4.70 E-6
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