R&S FSH
Spectrum Analyzer Mode
Performing Spectrum Measurements
Operating Manual 1309.6275.12 - 14
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Selecting the detector:
It is best to use the RMS detector. This detector correctly indicates the power
irrespective of the characteristics of the signal to be measured. The whole IF
envelope is used to calculate the power for each measurement point. The IF
envelope is digitized using a sampling frequency which is at least five times the
resolution bandwidth which has been selected. Based on the sample values, the
power is calculated for each measurement point using the following formula:
=
=
N
i
i
RMS
s
N
P
1
2
1
with
s
i
= linear digitized video voltage at the output of the A/D converter
N = number of A/D converter values per measurement point
P
RMS
= power represented by a measurement point
When the power has been calculated, the power units are converted into decibels
and the value is displayed as a measurement point.
In principle, the sample detector would be possible as well. Due to the limited
number of measurement points used to calculate the power in the channel, the
sample detector would yield less stable results.
2.1.4.1 Selecting a Standard
If you need to perform measurements that are conform to a telecommunications
standard, you can activate one of the predefined standards that are already stored in
the R&S FSH memory. Those predefined standards have already been set up to yield
the best results. However, the R&S FSH provides functionality to create new
configurations to perform measurements on other test setups as well.
M
Press the MEAS key.
M
Press the "Standard" softkey.
The R&S FSH opens a dialog box to select the standard.
M
Select one of the available standards.
M
Confirm the selection with the "Select" softkey.
The R&S FSH loads the configuration of the selected standard. It automatically
sets the optimal span, resolution bandwidth, video bandwidth, sweep time and
detector for the standard.
You can create and edit standards with the R&S FSH4View software and transfer them
to the R&S FSH via the USB or the LAN interface. The number of standards the
R&S FSH can store in its memory depends on the number of other data sets stored on
the R&S FSH. For more information see
C
"
Saving and Loading Instrument Settings and Measurement Results
