User`s guide

Functions and Measurements 3

N9320A Spectrum Analyzer 37

Resolving Small Signals Hidden by Large Signals

This example uses narrow resolution bandwidths to resolve

two input signals with 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 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

> Mkr -> Ref Lel

Figure 7 Unresolved small signal from large signal

Preset/

System

Frequency

BW/

Avg

SPAN

Peak

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.