R&S FSH
Spectrum Analyzer Mode
Configuring Spectrum Measurements
Operating Manual 1309.6275.12 - 14
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M
Press the AMPT key.
M
Press the "Unit" softkey.
The R&S FSH opens a submenu to select the display unit.
M
Select one of the available units.
The R&S FSH adjusts the labels of the vertical axis accordingly.
2.2.2.4 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.
M
Press the AMPT key.
M
Press the "Ref Offset" softkey.
The R&S FSH open an input field to
M
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 (
).
2.2.2.5 Setting the RF Attenuation
RF attenuation adjusts the input range inside the analyzer. It is coupled directly to the
reference level. If you have set a high reference level, RF attenuation is turned on in
10 dB steps according to the table below so that the input mixer always remains in the
linear range. The R&S FSH provides three attenuation modes.
C
Auto Low Distortion
If this mode is active, the R&S FSH sets the RF attenuation 10 dB higher
according to the table below, making the stress of the input mixer 10 dB less at the
specified reference level. If the spectrum is densely occupied with signals, e.g. in a
television cable network, the input mixer reduces the R&S FSH inherent spurious
products. However, the inherent noise display of the R&S FSH increases due to
the increased attenuation in front of the input mixer.
C
Auto Low Noise
If this mode is active, the R&S FSH sets the RF attenuation 10 dB lower. This
increases the sensitivity of the R&S FSH, which means that the inherent noise
display decreases due to the lower attenuation in front of the input mixer.
C
Manual
Manual selection of the attenuation.
