The Spectrum Application (RF Measurements)
R&S
®
FPL1000
236
User Manual 1178.3370.02 ─ 03
1. Select PRESET to reset the instrument.
2. Connect the signal to be measured to the RF INPUT connector on the
R&S
FPL1000.
3. Set the center frequency to
128
MHz
.
4. Reduce the frequency span to
1
MHz
.
Note:
Coupled settings. When the frequency span is defined, the resolution band-
width, the video bandwidth and the sweep time are automatically adjusted,
because these functions are defined as coupled functions in the presettings.
5. Select MKR to activate marker 1 and automatically set it to the maximum of the
trace.
The level and frequency values measured by the marker are displayed in the
marker information at the top of the display.
Note:
Performing a peak search. When a marker is initially activated, it automati-
cally performs the peak search function (as shown in the example).
If a marker was already active, select the PEAK SEARCH key or the "Peak" soft-
key in the MKR > menu in order to set the currently active marker to the maximum
of the displayed signal.
Increasing the Frequency Resolution
The frequency resolution of the marker is determined by the resolution of the trace. A
trace consists of 1001 trace points, i.e. if the frequency span is 1
MHz, each trace point
represents a span of approximately 1
kHz. This corresponds to a maximum uncertainty
of +/-
0.5
kHz.
You can increase the resolution of the trace by reducing the frequency span.
Reducing the frequency span to 10 kHz
► Reduce the frequency span to
10
kHz
.
The resolution of the trace is now approximately 10
Hz (10
kHz span / 1001 trace
points), thus, the precision of the marker frequency display increases to approxi-
mately
±
5
Hz.
Setting the Reference Level
The reference level is the level at the upper limit of the diagram. To achieve the widest
dynamic range possible for a spectrum measurement, use the entire level span of the
R&S
FPL1000. In other words, the highest level that occurs in the signal should be
located at the top edge of the diagram ( = reference level) or immediately below it.
Low Reference Levels
If the selected reference level is lower than the highest signal that occurs in the spec-
trum, the signal path in the R&S
FPL1000 is overloaded.
In this case, the message "IFOVL" is displayed in the error message field.
Measurements and Results
