Calibration
The Fluke Service Center Calibration System 7
7-9
gdw48.bmp
Figure 7-2. After Phase Adjustment
With the analog signal of both voltage and current channels in phase with the common
Phase Reference, the phase relationship between voltage and current is known with an
uncertainty, which is the sum of the residual error from the voltage and current
calibration adjustment.
The phase angles relative to the Phase reference of voltage channels other than L1 are
nonzero by default. Nevertheless, the same principle applies but with the phase angle
between the analog signal and the Phase Reference set to an appropriate nonzero value.
7-15. The Fluke Service Center Calibration System
As described above, the Fluke calibration system independently compares a voltage or
current channel to the system phase reference. Fourier analysis of sampled analog signals
yield amplitude and phase information which is used for calibration and adjustment. The
digitizing DMM is triggered externally by a signal from the 6100B. The trigger signal,
the Sample Reference, has a fixed phase relationship with the system Master Phase and
controls that start of the sample period. Thus the phase relationship of the analog signals
is fixed to the phase reference and is known.
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