User Manual

The Spectrum Application
R&S
®
FPC
122User Manual 1178.4130.02 ─ 05
4. Select the "N dB <x>" menu item to select the distance between the temporary
markers.
Note: The distance to the reference marker is by default 3 dB below the reference
marker.
12.10.4 Marker Demodulation
Access: "Mkr" > "Marker Demodulation"
The R&S FPC features an AM and FM demodulator to demodulate and monitor audio
signals. It demodulates the signal at the marker frequency.
You can listen to the demodulated signal with the internal speaker or headphones that
you can connect to the 3.5 mm headphone jack on the front of the R&S FPC.
When demodulating an AM modulated signal, the R&S FPC turns the video voltage
into an audible sound. You should therefore set the reference level to about the level of
the signal that you are demodulating.
If you perform measurements in the time domain, the R&S FPC demodulates continu-
ously. In the frequency domain, you can define a time period the R&S FPC demodu-
lates the signal at the marker frequency. The frequency sweep then stops at the
marker frequency for that time before finishing the sweep.
Remote commands required to configure marker properties:
●
Chapter 17.12.8, "Marker", on page 258
Selecting the demodulation type
1. Press the "Mkr" key to open the marker menu.
2. Select the "Marker Demodulation" menu item to open the marker demodulation
menu.
3. Select the "AM" or the "FM" menu item
The R&S FPC demodulates the signal according to the demodulation scheme you
have selected.
Note: If you turn on the demodulator, the R&S FPC automatically turns off the
noise marker or the frequency counter.
4. Select the "Demodulation Off" menu item to turn off marker demodulation.
Defining the demodulation length
1. Press the "Mkr" key to open the marker menu.
2. Select the "Marker Demodulation" menu item to open the marker demodulation
menu.
3. Select the "Time <x>" menu item.
The R&S FPC opens an input field to define the demodulation time.
Marker Functions