Fluke 9640A Series, Instruction Manual

Page: 248 / 324

9640A
Instruction Manual
5-58
Note
If a power sensor having different characteristics than the one specified is
used, it may not be necessary to change types at this point. Consult the
power sensor manufacturer’s manual for input signal level specifications.
17. Replace the thermal power sensor with the diode (low-power) sensor in the test setup.
Note
The diode-based power sensor may exhibit frequency dependent linearity
errors, and additional corrections for these errors must also be applied.
Note
The following steps facilitate the mid-level flatness adjustment of the 50 Ω
Leveling Head using a power meter and sensor.
18. Set the UUT to
OPER
.
19. Repeat steps 13 through 15 for all points requiring the use of the power meter and
diode sensor (the UUT text box will indicate
Use Power Meter
)
.
Set the UUT to
STBY
.
20. Disconnect the power meter and low-power sensor from the Leveling Head. Connect
the UUT 50
Ω
Leveling Head to the input of the spectrum analyzer/measuring
receiver.
Note
The following steps facilitate the low-level flatness adjustment of the 50 Ω
Leveling Head using a spectrum analyzer/measuring receiver.
21. Set the UUT to
OPER
.
22. Set the spectrum analyzer reference level, span, resolution and/or video bandwidth as
necessary to make a high-quality level measurement at the applied level and
frequency.
Note.
For each frequency it is important to maintain consistent analyzer/receiver
settings as the target amplitude changes. For any given frequency the
analyzer setting can be to suit, but that setting must be maintained for all
amplitudes at that frequency after the transfer point. In particular, analyzer
attenuator, reference level and resolution bandwidth settings must not
change. Typically there are 3 or 4 amplitudes per frequency point during
which the analyzer settings must be static.
23. Using the blue arrow keys and rotary knob, edit the UUT
Actual
output until the
spectrum analyzer display indicates the
Target
value stated. Press Accept Target .
24. Press
Next Target
.
25. Repeat steps 22 through 24 for all points requiring the use of the spectrum analyzer
until all Leveling Head adjustments are completed.
26. Press
Previous Menu
. The 50 Ω Leveling Head adjustment is now complete.
27. If additional Leveling Heads are to be adjusted, substitute the remaining Leveling
Head(s) for the one currently attached and perform the appropriate (50 or 75 Ω )
Leveling Head adjustment process. If not, press
Exit
twice to return the UUT to a
normal operating state.