Specifications

22 Chapter 2
Measuring Multiple Signals
Decreasing the Frequency Span Around the Signal
Measuring Multiple Signals
Decreasing the Frequency Span Around the
Signal
Using the analyzer signal track function, you can quickly decrease the
span while keeping the signal at center frequency. This is a fast way to
take a closer look at the area around the signal to identify signals that
would otherwise not be resolved.
This procedure uses signal tracking and span zoom to view the analyzer
50 MHz reference signal in a 200 kHz span.
Step 1. Perform a factory preset:
Press
Preset, Factory Preset (if present).
Step 2. Enable the internal 50 MHz amplitude reference signal of the analyzer
as follows:
(PSA)
Press
Input/Output, Input Port, Amptd Ref.
(ESA E4401B and E4411B)
Press
Input/Output, Amptd Ref (On).
(ESA E4402B, E4403B, E4404B, E4405B, E4407B and E4408B)
Connect a cable from the front panel AMPTD REF OUT to the analyzer
RF input:
Press
Input/Output, Amptd Ref Out (On).
Step 3. Set the start frequency to 20 MHz and the stop frequency to 1 GHz:
Press
FREQUENCY Channel, Start Freq, 20, MHz.
Press
FREQUENCY Channel, Stop Freq, 1, GHz.
Step 4. Place a marker at the peak:
Press
Peak Search.
Step 5. Turn on the signal tracking function to move the signal to the center of
the screen (if it is not already positioned there):
Press
FREQUENCY Channel, Signal Track (On).
See the left-side of figure Figure 2-11. (Note that the marker must be on
the signal before turning signal track on.)
NOTE Because the signal track function automatically maintains the signal at
the center of the screen, you can reduce the span quickly for a closer
look. If the signal drifts off of the screen as you decrease the span, use a
wider frequency span. (You can also use
Span Zoom, in the SPAN menu,
as a quick way to perform the
Peak Search, FREQUENCY, Signal Track,
SPAN key sequence.)