The Spectrum Application
R&S
®
FPC
103
User Manual 1178.4130.02 ─ 07
Reference level
Preamplifier OFF
RF attenuation
Preamplifier ON
RF attenuation
Low noise
Low distortion
Low noise
Low distortion
21 dBm to 25 dBm
35 dB
40 dB
40 dB
40 dB
26 dBm to 30 dBm
40 dB
40 dB
40 dB
40 dB
Preamplifier
The internal 20
dB preamplifier is another hardware component to control measure-
ment sensitivity.
When you turn on the preamplifier, all signals are amplified by 20
dB.
It has the following effects on measurements.
●
The preamplifier allows you to detect even weak signals.
●
The preamplifier reduces the noise figure of the R&S
FPC and thus increases its
sensitivity. Thus, it is recommended to use the preamplifier for measurements that
require a high sensitivity.
●
The preamplifier reduces the dynamic range. If you want to measure with the maxi-
mum dynamic range, you should turn off the preamplifier.
The gain of the preamplifier is automatically considered in the level display.
Turning the preamplifier on and off
1. Press the "Ampt" key to open the amplitude menu.
2. Select the "Preamplifier" menu item.
The R&S
FPC turns the preamplifier on and off.
The status of the preamplifier is indicated in the status bar.
14.4.3
Scale of the Y-Axis
The scale of the y-axis depends on the unit you have selected for the measurement
and the display range.
Selecting the display unit
A spectrum analyzer usually shows signal levels in the unit dBm.
If necessary, you can also select other units. In that case, the analyzer automatically
converts the results into the selected unit.
1. Press the "Ampt" key to open the amplitude menu.
2. Select the "Unit" menu item to open the unit menu.
3. Select the one of the available display units.
The R&S
FPC adjusts the labels of the vertical axis accordingly.
Amplitude Configuration
