Measuring forward and reflected power
R&S FSH
1145.5973.12 4.80
E-11
Press the ->REF softkey.
The R&S FSH accepts the currently measured level as
the reference level and displays the measured level
difference relative to the reference level in dB. The unit
(UNIT) is automatically set to dB REL... .
The reference level is displayed in the upper left corner
of the screen (in this case: Ref: -4.8 dBm).
The reference level can be adjusted in the
REFERENCE entry box by means of the rotary knob,
the cursor keys or the number keys.
Confirm the reference level with the ENTER key or
the ->REF softkey.
To switch off the relative measurement to absolute
values, press the POWER DISPLAY softkey.
Select the Forward Power... parameter.
Select dBm or Watt for forward power indication.
To ensure that true results are output when measuring modulated signals, the R&S FSH offers the
possibility of taking correction values into account for a number of common transmission standards.
Press the STANDARD softkey.
A menu with the selectable standards opens.
Select the desired standard using the rotary knob
or the cursor keys.
Confirm with the ENTER key or by pressing the
STANDARD softkey again.
The selected standard is displayed in the upper right
corner of the screen.
Taking additional attenuation into account
When the directional power sensor is connected to a test point not directly but via a cable, the influence
of cable attenuation can be taken into account. For this purpose, the cable attenuation for the
measurement frequency in question is to be entered, i.e. as a positive dB value if the power and
matching are to be measured at the source and the cable is connected between the source and the
power sensor, and as a negative dB value if the power and matching are to be measured at the load
and the cable is connected between the load and the power sensor. The directional power sensor then
corrects the power and matching values to produce the results that would have been obtained if it had
been directly connected to the test point.
