User`s guide

92 Agilent E5505A User’s Guide
4 Expanding Your Measurement Experience
Making the measurement
1 Click the Continue button when you have completed the beatnote check
and are ready to make the measurement.
2 When the PLL Suppression Curve dialog box appears, select View
Measured Loop Suppression, View Smoothed Loop Suppression, and
View Adjusted Loop Suppression. See Figure 57 on page 92.
• There are four different curves for this graph. (For more information about
loop suppression verification, refer to Chapter 15, “Advanced Software
Features.”)
a “Measured” loop suppression curve—this is the result of the loop
suppression measurement performed by the E5505A system.
b “Smoothed” measured suppression curve—this is a curve-fit
representation of the measured results, it is used to compare with the
“theoretical” loop suppression.
c “Theoretical” suppression curve—this is the predicted loop suppression
based on the initial loop parameters defined/selected for this particular
measurement (kphi, kvco, loop bandwidth, filters, gain, and others).
d “Adjusted” theoretical suppression curve—this is the new “adjusted”
theoretical value of suppression for this measurement. It is based on
changing loop parameters (in the theoretical response) to match the
“smoothed” measured curve as closely as possible.
Figure 57 Suppression selections