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R&S FSH
Spectrum Analyzer Mode
Configuring Spectrum Measurements
Operating Manual 1173.6275.12 - 30
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However, increasing resolution does not increase the accuracy of, for example, the
marker level readout, but only makes it easier to read values off the trace.
You can also select a linear scale for the vertical axis. In that case, the power levels
are expressed as a percentage of the reference level. Linear scaling is useful to
display AM modulated carriers in the time domain, for example.
► Press the AMPT key.
► Press the "Range / Ref Pos" softkey.
The R&S FSH opens a submenu to select the display range.
► Select the display range you need (“Manual Range” allows you to select a custom
range).
The R&S FSH adjusts the vertical axis accordingly.
3.2.2.3 Selecting the Display Unit
By default, the vertical axis (and therefore the reference level) is scaled in dBm.
However, the units dBmV, dBµV, Watt and Volt are also available. Selecting the right
unit is relevant for the marker level display because the unit of the marker level is the
same as that of the reference level.
► Press the AMPT key.
► Press the "Unit" softkey.
The R&S FSH opens a submenu to select the display unit.
► Select one of the available units.
The R&S FSH adjusts the labels of the vertical axis accordingly.
3.2.2.4 Setting a Reference Offset
You can define a reference offset for the reference level. With a reference offset, you
can increase the reference level by a certain amount. This is useful, for example, if an
attenuator or amplifier has been inserted before the RF input. The R&S FSH
automatically takes the loss or gain into account when the level is displayed and no
manual calculations are necessary. A loss introduced at the RF input must be entered
as a positive number and a gain as a negative number.
► Press the AMPT key.
► Press the "Ref Offset" softkey.
The R&S FSH open an input field to
► Enter the offset you need.
The R&S FSH includes the offset in the measurement.
To indicate an offset other than 0, the R&S FSH puts a red dot at the "Ref:"
hardware setting (
).