Specifications

Chapter 9 73
Measuring Digital Communications Signals
Making Statistical Power Measurements (CCDF)
Measuring Digital Communications
Signals
Step 7. Change the measurement bandwidth to 1 MHz:
Press
Meas Setup, Meas BW, 1, MHz.
Figure 9-5 Reducing the measurement bandwidth to 1 MHz
NOTE If you choose a measurement bandwidth setting that the analyzer
cannot display, it automatically sets itself to the closest available
bandwidth setting.
Step 8. Change the number of measured points from 100,000 (100k) to 1,000
(1k):
Press
Meas Setup, Counts, 1, kpoints.
Reducing the number of points decreases the measurement time,
however the number of points is a factor in determining measurement
uncertainty and repeatability. Notice how the displayed plot loses a lot
of its smoothness. You are gaining speed but reducing repeatability and
increasing measurement uncertainty.
NOTE The number of points collected per sweep is dependent on the sampling
rate and the measurement interval. The number of samples that have
been processed are indicated at the top of the screen. The graphical plot
is continuously updated so you can see it getting smoother as
measurement uncertainty is reduced and repeatability improves.
Step 9. Change the scaling of the X-axis to 1 dB per division to optimize your
particular measurement:
Press
SPAN X Scale, Scale/Div, 1, dB.