Fluke 9640A Series, Instruction Manual

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9640A
Instruction Manual
5-52
The Instrument calibration adjustment must be performed in the order presented, as
subsequent steps rely on measurement values entered during previous steps. Although not
recommended, it is possible to perform a partial calibration adjustment based on the
Instrument function. For example, if it is desired to adjust only a specific output level of
the Instrument, the operator may skip to the first step of the affected adjustments and
proceed from that point on. To do so, depress the
Find Point
soft key, then use the blue
arrow keys, rotary knob, or numeric keypad (followed by
ENTER
) to select the point
number desired, then press
Go to Point
to complete the process. (The information
provided in the text box below the Adjustment Point may be used as an aid to find the
point desired.)
The specifications listed in Chapter 1 contain some conditions for which performance is
not warranted or specified as “typical” (for example, at frequencies below 100kHz at
levels below -47 dBm, modulation, etc). The adjustment sequence also includes points
for adjusting performance in these areas, which have no impact on the warranted
performance of the 9640A. These additional points are adjusted at manufacture or
following repair but need not be routinely re-adjusted during normal periodic
recalibration operations. Accordingly, the relevant steps in the calibration adjustment
sequence may be omitted if measurement capability is not available.
A spreadsheet file containing a detailed list of calibration adjustment points is available
on the CD supplied with the Instrument.
Rear Panel Calibration Enable Switch
The rear panel calibration switch must be set to the
ENABLE
(up) position prior to
attempting any of the calibration adjustment procedures described below. On completion
of all the required calibration adjustments, return the rear panel calibration switch to the
DISABLE
(down) position and fit a calibration integrity seal over the switch access.
Reference Frequency Adjustment
Equipment required for this test:
•
Frequency Counter
•
Frequency Standard
Use the following procedure to adjust the frequency of the internal reference:
1.
Warm up the UUT (continuous operation) for 24 hours, minimum.
2. Connect the 10 MHz output from the frequency standard to the EXT REF IN on the
frequency counter (rear panel) using a BNC male – male cable assembly. Set the
frequency counter for external time base reference.
3. Connect the REF FREQUENCY OUTPUT (on rear) from the UUT to the Channel A
input on the frequency counter using a BNC male – male cable. Set the frequency
counter input impedance to 50
Ω
. See Figure 5-1 for equipment connections.
4. On the UUT enable the REF FREQUENCY OUTPUT at 10 MHz.
5. On the UUT, press

, followed by the soft key
Calibration
, and then softkey
Calibrate Instrument
.
6. Using the keypad, enter the password, followed by the
ENTER
key.
Note
At shipment, the factory default password is “2, SPACE, 3, SPACE, 5,
SPACE, 7”.
7. Press the soft key
Adjust Frequency
.