Keysight N9320B - Resolving Small Signals Hidden by Large Signals

39
Functions and Measurements
Measuring Multiple Signals
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 > 300 > MHz
Press > 30 > kHz
Press > 500 > kHz
4 Set the 300 MHz signal to the reference level:
Press
Press
> Mkr -> Ref Lvl
Figure 3-7 Unresolved small signal from large signal
Preset/
System
Frequency
BW/
Avg
SPAN
Peak
Search
Marker
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.