R&S FSH
Spectrum Analyzer Mode
Configuring Spectrum Measurements
Operating Manual 1309.6275.12 - 14
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If you have to switch between full span and a smaller span, you can do so without
having to enter the numeric values.
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Press the SPAN key.
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Press the "Full Span" softkey.
The R&S FSH displays the spectrum over its entire frequency range.
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Press the "Last Span" softkey.
The R&S FSH restores the span that you have set just before displaying the entire
frequency range.
Time domain measurements
You can also activate time domain measurements without having to enter the value
manually. When measuring in the time domain, the span is 0 Hz. In that state, the
R&S FSH measures the signal at the current center frequency only. Instead of
displaying the spectrum, the R&S FSH shows the signal power over a certain time
period. The horizontal axis becomes the time axis. The display always starts at 0 s and
stops after the currently set sweep time.
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Press the SPAN key.
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Press the "Zero Span" softkey.
The R&S FSH sets a span of 0 Hz and performs the measurement in the time
domain.
2.2.2 Configuring the Vertical Axis
All relevant settings to configure the vertical axis are available in the amplitude menu.
You can access it via the AMPT key.
2.2.2.1 Setting the Reference Level
The reference level is represented graphically by the grid line at the top of the diagram.
The reference level sets the input signal gain up to the display stage. If the reference
level is low, the gain is high. That means that even weak signals are displayed clearly.
If you are measuring strong signals, you have to set a high reference level in order to
prevent an overload of the signal path of the analyzer and to keep the signal within the
display range. If you are measuring the spectrum of a composite signal, make sure that
the reference level is high enough to cover all signals and that all signals are within the
measurement diagram.
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Press the AMPT key.
When you press the AMPT key, the R&S FSH automatically opens an input field to
define the center frequency. If the input field is inactive, you can open it with the
"Ref Level" softkey.
