Fluke 6060B Instruction Manual page 140

MAINTENANCE
CALIBilATION ADJUSTMENTS
4. AM Depth Adjustment
TEST EQUIPMENT
DVM
Modulation Analyzer LFSSG
REMARKS
The U UT must be operated at room temperature for at least one hour with the module
plate covers in place before continuing with this adjustment procedure.
This adjustment dlreetly affeets the output level and should not
lndlserlmlnately.
This adjustment is normally required only when components in the A M signal processing
circuits have been replaced, or the adjustment has been changed or shifted. lf this
adjustment is made, it is necessary to perform the R F level adjustment after the AM depth
adjustment has been made.
PROCEDUR E
Adjust the AM depth potentiometer R421 for 90% A M depth as measured with the
Modulation Analy t:cr when the UUT is programmed to 90% AM.
k. Repeat the previous four steps until the difference between the power
measurements is 20 ± 0 . 1 dBm. This adjustment should require three or
fewer iterations.
Program the U UT to + 12 dBm, using the EDIT keys. Note the Power Meter
reading.
Program the UUT for +2 dBm using the EDIT keys. Verify that the Power
I.
Meter reading is 10 d B ±.2 dB below the previous reading.
m. Program the UUT for [SPCL] [0][0). This enables amplitude level
correction and disables amplitude fixed range.
n. Disconnect the Power Sensor from the UUT, and replace the Detector
Offset adjustment access screw.
a. Remove the AM depth adjustment access screw from the bottom module
plate cover.
b. Connect the output of the LFSSG to the UUT MOD IN connector and to
the DVM using a BNC Tee.
c. Program the UUT to [RCL] [9][8], then program the UUT for 350 M Hz, + I
dBm, and EXT A M a t 90% A M depth.
d. Program the LFSSG for I kHz and a voltage of 0. 7071 rms, as measured by
the DVM.
CAUTION
adjusted
be
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