Fluke 8508A - SPOT FREQUENCY (1 to 6) Menu; Special Calibration; SPCL Menu

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Adjustment and Verification
Calibration Menus
SPOT FREQUENCY (1 to 6) Menu
Enter this menu by pressing
Enter in the SPOT (1 to 6) RMS menu, which also stores the
RMS value keyed in during this menu. The value in the
SPOT FREQUENCY (1 to 6)
menu is the measured frequency of the present adjustment input signal.
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SPOT FREQUENCY n Menu
Pressing the SAMPLE key causes the selected ACV range to be spot-adjusted at the
adjustment signal frequency. The frequency value is stored and can be viewed from the
UTILITY menu. If ACV Spot Frequency mode is selected, any subsequent measurement
on this range whose frequency is within ±10 % of the stored frequency is accuracy
enhanced by reducing frequency response flatness errors.
Adjust the spot at a new frequency:
To adjust the spot at a new frequency, change the input signal to the desired new
frequency and press
SAMPLE as before.
 Reverts to the
SPOT CAL menu with the original Spot adjustment intact.
Special Calibration
The SPCL menu provides alignment of the ADC and adjustment of the frequency
counter.
It also allows the High Voltage Linearity Pre-Adjustment to be performed and a section
of the Non-Volatile memory to be cleared for test purposes. These facilities are used in
the factory for initial pre-adjustment processes; they should not require access during the
life of the instrument unless repairs have been carried out. They appear here for
completeness.
SPCL Menu
The SPCL menu appears after pressing the Special key in the CALIBRATION menu. At
the same time the instrument is placed in special calibration mode, the Special
CAL
legend appears on the main display.
When in Special
CAL mode the following front panel keys remain inoperative: CLEAR,
TEST, OFFSET, PRT and INPUT. Also, the function of the SAMPLE key changes to
become the trigger key for initiating the Hvlin adjustment operation.
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SPCL Menu
The SPCL menu provides the selection:
 Aligns the different resolutions available from the instrument's analog-to-
digital converter, so that there are no significant differences in readings when
changing resolutions with a constant input value. No external input signals
are required for this adjustment. Adjustment is initiated directly by making
this selection from the SPCL menu.
 Calibrates the frequency counter against an external source. Adjustment is
initiated directly by making this selection from the SPCL menu.
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