Fluke 6060B Instruction Manual page 145

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2. FM Adjustments, R82, R90, AND R87
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TEST EQUIPMENT
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Modulation Analyzer
LFSSG
DVM
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REMARKS
The FM Cal adjustment, R82, sets the overall deviation accuracy, whereas the Low-Rate
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Deviation Adjustment, R90, equalizes the low and high rate deviation. The FM Flatness
Adjustment, R87, equalizes the deviation across the band from 0.4 to 10 kHz.
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PROCEDURE
The FM deviation of the U UT, as measured with the Modulation Analyzer, is adjusted to
agree with the programmed deviation at 10-kHz and 0.4-kHz rates by adjusting R82,
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R90, and R87, respectively.
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b. Connect the output of the LFSSG to the UUT MOD IN connector and to
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c. Connect the UUT RF OUTPUT to the Modulation Analyzer input.
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e. Program the UUT to the [RCL] [9)[8]. Then program the UUT to 385.5-
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f.
g. Adjust R82 for 100.0 kHz, as measured by the Modulation Analyzer.
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h. Program the LFSSG to 0.4 kHz and 0.707 1 V rms, as measured by the
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J.
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k. Repeat steps f through j until the deviation flatness is 100.0 kHz ± 0.3 kHz .
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l.
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m. Turn the UUT EXT FM on.
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Remove the instrument cover and the FM CAL, FM flatness, and Low­
Rate Deviation adjustment access screws from the cover of the module
the DVM. using a BNC tee.
Program the Modulation Analyzer to measure FM + peak ina 0.05-kHzto
> 200-kHz bandwidth.
MHz, 7 dBm, EXT FM, 99.9-kHz deviation.
Program the LFSSG to 1 0 kHz and 0.707 1 V rms as measured by the DVM.
DVM.
Program the LFSSG to I kHz, and adjust R87 for 100.0 kHz as measured on
the Modulation Analyzer.
Turn the UUT EXT FM off, and note the Modulation Analyzer peak
deviation (noise) reading.
MAINTENANCE
CA�IBRATION ADJUSTMENTS
4C- 1 3