User`s guide

16-8 Agilent Technologies E5500 Phase Noise Measurement System
Advanced Software Features
PLL Suppression Verification Process
PLL Suppression
Information
The PLL Suppression View graph has been updated to allow measured,
calculated (adjusted), and theoretical information to be examined more
closely. When the “Always Show Suppression Graph” is selected, the
following graph (Figure 16-3 on page 16-8) is provided.
Figure 16-3 Default PLL Suppression Verification Graph
There are four different curves available for the this graph:
1. “Measured” loop suppression curve (Figure 16-4) - this is the result of
the loop suppression measurement performed by the E5500 system;
2. “Smoothed” measured suppression curve (Figure 16-5 on page 16-9)-
this is a curve-fit representation of the measured results, it is used to
compare with the “theoretical” loop suppression;
3. “Theoretical” suppression curve (Figure 16-6 on page 16-10) - this is the
predicted loop suppression based on the initial loop parameters
defined/selected for this particular measurement (kphi, kvco, loop
bandwidth, filters, gain, etc).
4. “Adjusted” theoretical suppression curve (Figure 16-7 on page 16-10
thru Figure 16-9 on page 16-11) - 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.