User`s guide

Absolute Measurement Examples 6
Agilent E5505A User’s Guide 183
Refer to Chapter 14, “Evaluating Your Measurement Results if you are not
familiar with the relationship between the PLL capture range and the peak
tuning range of the VCO.)
The beatnote frequency is set by the relative frequency difference between the
two sources. If you have two very accurate sources set at the same frequency,
the resulting beatnote will be very close to 0 Hz.
Searching for the beatnote will require that you adjust the center frequency of
one of the sources above and below the frequency of the other source until the
beatnote appears on the oscilloscope’s display.
If incrementing the frequency of one of the sources does not produce a
beatnote, you will need to verify the presence of an output signal from each
source before proceeding.
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 130 on page 184.
NOTE
If the center frequencies of the sources are not close enough to create a beatnote within
the capture range, the system will not be able to complete its measurement.
Figure 129 Oscilloscope display of a beatnote from the test set Monitor port
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