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Document Part No. E5500-90024Ed. 1.0
5
The following messages will appear on the display as the system
performs the calibration routines. (You will have time to read
through these message descriptions while the system completes
the routines.)
Determining Presence of Beat Note...
An initial check is made to verify that a beatnote is present within
the system's detection range.
Verifying zero-beat...
The frequency of the beatnote is measured to see if it is within 5% of
the estimated Peak Tuning Range of the system. The system's Peak
Tuning Range is the portion of the voltage-controlled-oscillator
(VCO) source's tuning range being used for the measurement.
When the system measures the phase noise of a signal source using
the Phase Lock Loop technique (the technique being used in this
example) it requires that one of the two sources used in the setup is a
VCO. As you will see later in this demonstration, you will be required
to estimate the tuning range of the VCO source you are using when
you set up your own Phase Lock Loop measurements.
Zero beating sources...
The center frequencies of the sources are now adjusted, if necessary,
to position the beatnote within the 5% range. The adjustment is made
with the tune voltage applied to the VCO source set at its nominal or
center position.
Measuring the VCO Tuning Constant...
The tuning sensitivity (Hz/V) of the VCO source is now precisely
determined by measuring the beatnote frequency at four tune voltage
settings across the tuning range of the VCO source. Linearity across
the tuning range is also verified
Measuring the Phase Detector Constant...
The transfer characteristics (V/rad) of the test set's phase detector
are now determined for the specific center frequency and power level
of the sources being measured.
Measuring PLL suppression...
The required correction data is created to compensate for the phase
noise suppression which occurs within the bandwidth of the phase
lock loop created for this measurement.
E5500 Phase Noise Measurement System Version A.02.00
Expanding Your Measurement Experience
Testing the Agilent 8644B Internal/External 10 MHz
5
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