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.
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