Specifications

20 Chapter 2
Measuring Multiple Signals
Resolving Small Signals Hidden by Large Signals
Measuring Multiple Signals
Resolving Small Signals Hidden by Large
Signals
This procedure uses narrow resolution bandwidths to resolve two input
signals with a frequency separation of 155 kHz and an amplitude
difference of 60 dB.
Step 1. Connect two sources to the analyzer input as shown in Figure 2-6.
Step 2. Set one source to 300 MHz at −10 dBm. Set the second source to
300.05 MHz, so that the signal is 50 kHz higher than the first signal.
Set the amplitude of the signal to
−70 dBm (60 dB below the first
signal).
Step 3. Set the analyzer as follows:
Press
Preset, Factory Preset (if present).
Press
FREQUENCY Channel, Center Freq, 300, MHz.
Press
BW/Avg, 30, kHz.
Press
SPAN X Scale, Span, 500, kHz.
NOTE If the signal peak is not present on the display, span out to 20 MHz,
turn signal tracking on, span back to 2 MHz and turn signal tracking
off:
Press
SPAN, Span, 20, MHz.
Press
Peak Search, FREQUENCY, Signal Track (On).
Press
SPAN, 2, MHz.
Press FREQUENCY, Signal Track (Off).
Step 4. Set the 300 MHz signal to the reference level:
Press
Peak Search, Mkr →, Mkr → Ref Lvl.
NOTE The ESA 30 kHz filter shape factor of 15:1 (PSA is 4.1:1) has a
bandwidth of 450 kHz at the 60 dB point (PSA has a BW of 123 kHz).
The half-bandwidth (225 kHz for ESA and 61.5 kHz for PSA) is NOT
narrower than the frequency separation of 50 kHz, so the input signals
can not be resolved.