Specifications

Chapter 3 29
Measuring a Low−Level Signal
Using the Average Detector and Increased Sweep Time
Measuring a Low
−
Level Signal
Using the Average Detector and
Increased Sweep Time
When the analyzer’s noise masks low-level signals, changing to the
average detector and increasing the sweep time smooths the noise and
improves the signal’s visibility. Slower sweeps are required to average
more noise variations.
Step 1. Refer to the first procedure “Reducing Input Attenuation” on page 26 of
this chapter and follow steps 1, 2 and 3.
Step 2. Select the average detector:
Press
Det/Demod, Detector, Average.
A “#” mark appears next to the Avg annotation, indicating that the
detector has been chosen manually (see Figure 3-4).
Step 3. Increase the sweep time to 100 ms:
Press
Sweep, Sweep Time, ↑.
Note how the noise smooths out, as there is more time to average the
values for each of the displayed data points.
Step 4. With the sweep time at 100 ms, change the average type to
log averaging:
(ESA) Press
BW/Avg, Avg Type, Video Avg.
(PSA) Press
BW/Avg, Avg/VBW Type, Log-Pwr.
Figure 3-4 Varying the Sweep Time with the Average Detector