Measurements and Results
R&S
®
FSW
141
User Manual 1173.9411.02 ─ 43
is equal to the frequency spacing, the spectrum display shows a level drop of 3 dB pre-
cisely in the center of the two signals. Decreasing the resolution bandwidth makes the
level drop larger, which thus makes the individual signals clearer.
In this measurement example we will analyze two signals with a level of -30
dBm each
and a frequency spacing of 30
kHz.
Figure 7-5: Test setup
Table 7-3: Signal generator settings (e.g. R&S SMW)
Level
Frequency
Signal generator 1
-30 dBm
128,00 MHz
Signal generator 2
-30 dBm
128,03 MHz
1. Select [PRESET] to reset the instrument.
2. Set the center frequency to
128.015
MHz
.
3. Set the frequency span to
300
kHz
.
4. Set the resolution bandwidth to
30
kHz
and the video bandwidth to
1
kHz
.
Note:
Larger video bandwidths. The video bandwidth is set to 1
kHz in order to
make the level drop in the center of the two signals clearly visible. At larger video
bandwidths, the video voltage that results from envelope detection is not suffi-
ciently suppressed. This produces additional voltages, which are visible in the
trace, in the transition area between the two signals.
Basic Measurements
