Resolving Small Signals Hidden By Large Signals - Keysight Technologies N9322C User Manual

Functions and Measurements
Measuring Mul tiple Signals

Resolving Small Signals Hidden by Large Signals

N O T E
42
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.
Connect two sources to the RF IN as shown in
1
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
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.
Figure 3-7 Unresolved small signal from large signal
Figure 3-4
.