Keysight Technologies N9322C, Руководство пользователя, Страница: 50 / 214

Functions and Measurements
Measuring Multiple Signals
42
Resolving Small Signals Hidden by Large Signals
This example uses narrow resolution bandwidths to resolve
two RF signals that have a frequency separation of 50 kHz
and an amplitude difference of 60 dB.
1
Connect two sources to the
RF IN
as shown in
Figure 3-4
.
2
Set one source to 300 MHz at –10 dBm. Set the other source
to 300.05 MHz at –70 dBm.
3
Set the analyzer as follows:
Press
Preset
. (With
Preset Type
of
Factory
)
Press
Frequency > 300 > MHz
Press
BW > 30 > kHz
Press
Span > 500 > kHz
4
Set the 300 MHz signal to the reference level:
Press
Peak Search
Press
Marker > Mode > Mkr -> Ref Lvl
Figure 3-7 Unresolved small signal from large signal
NOTE
The 30 kHz filter shape factor of 15:1 has a bandwidth of 450 kHz at the 60
dB point. The half-bandwidth (225 kHz) is NOT narrower than the
frequency separation of 50 kHz, so the input signals can not be resolved.