BNC 7000 Series User Manual User Manual
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1. Determine the phase detector constant. Start this step by pressing the “Measure” button in step1.
Mechanically or digitally tuned phase shifters must be manually adjusted to provide at least 180
degrees phase shift to derive the phase detector constant. If already known for a given setup, the
phase detector constant can be manually entered. In case “Analog Tune” is selected and voltage
controlled phase shifters are used, this step is performed automatically by the instrument and can
be omitted.
2. Once the phase detector constants are known, the phases must be adjusted to obtain phase
quadrature. Start this step by pressing the “Measure” button in step 2. Now, the phase difference
between signal pairs at RF IN and REF IN (1 and 2) must be adjusted using the external phase
shifters to achieve approximate phase quadrature (90 degree phase difference) as shown in
Figure 17. The GUI shows a tolerance window of ±3 degrees. In case “Analog Tune” is selected
and voltage controlled phase shifters are used, this step is performed automatically by the
instrument and can be omitted.
3. Finally, the actual measurement can be started by pressing the green “Measure” button as shown
in Figure 18. Measurement can be stopped and restarted without need of performing step 1 and 2
each time.
Figure 17 Additive phase noise measurement tab (Time Domain) during step 2, automatically
adjusting the phase to quadrature.
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