Measuring with Transducer Factors
R&S FSH
1145.5973.12 4.124
E-11
If a transducer is switched on, TRD is displayed in the
top right-hand corner of the diagram on the R&S FSH.
The complete name of the selected transducer is
displayed in the status line (press the STATUS key
and scroll downward in the list), or in the list of
transducer factors (entry highlighted in red).
The example (Fig. right) shows the transducer factor of
the R&S HL223 antenna, which is defined as between
200 MHz and 1300 MHz. The R&S FSH therefore
displays the noise in this frequency range as a function
of frequency incremented by the transducer factor.
Outside the transducer range, the R&S FSH sets the
transducer factor at zero, i.e. measurements in this
range do not yield conclusive results.
A second transducer factor can be switched on with
the TRANSD dB softkey, which is then added to the
first. The unit of the second transducer factor must
always be the relative unit dB as otherwise an addition
would not be useful. When TRANSD DB is selected,
the R&S FSH offers only the transducer factors stored
in the instrument with dB as the unit.
Unit for measurements with transducers
If the unit of the transducer is dB, the units dBm, dBmV or dB
O
V remain unchanged. The linear units
Volt and Watt are not permissible. They are deactivated in the units menu.
If the unit of the transducer is dB
O
V/m or dB
O
A/m, this unit is also used for the R&S FSH level display.
This means that both the level axis of the diagram and the level at the marker position are assigned the
unit of the transducer. If dB
O
V/m is selected as the transducer unit, switchover to absolute level
indication in V/m is possible.
Switchover to V/m level indication:
Press the AMPT key.
Press the UNIT softkey.
In the UNIT menu, select V by means of the rotary knob or the cursor keys and confirm with the
ENTER key or by pressing the UNIT softkey again.
If a transducer with the unit dB
O
A/m is switched on, no other unit can be selected in the AMPT menu.
Level indication is entirely in dB
O
A/m.
Reference level settings for measurements with transducers
The transducer shifts the trace by its value as a function of frequency. Positive transducer values
increase the level, negative values reduce it. To ensure that the trace is always within the diagram, the
R&S FSH adjusts the reference level accordingly. The reference level is shifted by the maximum
transducer value in the positive or negative direction.
