Measuring the occupied bandwidth
R&S FSH
1145.5973.12 4.46
E-11
Selecting a standard
The R&S FSH offers a default for measuring the occupied bandwidth for different standards. It is also
possible to define and save user-specific configurations.
Press the STANDARD softkey.
A table with the available standards opens.
Using the rotary knob or the cursor keys, select the
appropriate standard.
Confirm your selection with the ENTER key or the
STANDARD softkey.
The selected standard is set. The optimal span,
resolution bandwidth, video bandwidth, sweep time
and detector for the standard are selected
automatically.
If USER is selected, the R&S FSH restores the last setting used in the USER mode for measuring the
occupied bandwidth. The R&S FSH automatically makes changes to the setting so that it is again
available when USER is called again.
The following should be noted when changes to the settings are made:
•
The span is always coupled to the channel bandwidth (CHANNEL BW). When changes are made,
the R&S FSH automatically sets the appropriate span (= 5 x channel bandwidth).
•
The resolution bandwidth should be between 1% and 4% of the channel bandwidth. This ensures
that the occupied bandwidth is measured with high accuracy.
•
The video bandwidth must be at least three times the resolution bandwidth. This prevents incorrect
results due to the compression of signal peaks by the video filter.
•
The RMS detector is recommended. This ensures that the power measurement is always correct
irrespective of the waveform being investigated.
•
The sweep time must be set so that the result is stable. If the sweep time is increased, the
R&S FSH also increases the integration time for the RMS detector and thus ensures more stable
measured values.
