Fluke 6060B Instruction Manual page 138

MAINTENANCE
CALIBRATION ADJUSTMENTS
2. Modulation Oscillator Level Adjustment
This adjustment sets the modulation oscillator level.
TEST EQU I P M ENT
M odulation Analyzer
DVM
Low Frequency Synthesized Signal Generator (LFSSG)
REMARKS
The modulation oscillator adjustment is normally required only when components in the
modulation oscillator or modulation switching circuits have been replaced or th
adjustment has been changed or has shifted.
PROCEDURE
The AM depth, with internal modulation, is adjusted via R419 to equal the AM depth
with a ! -volt peak e
Analyzer.
4C-6
d. Adjust R309 for an indication of +O mY ± 0.5 mY.
c.
Program the OUT RF OUTPUT to ON.
f Replace the access screws.
x
ternal modulation si
a. Gain access to the access screws for R419 by remov
instrument cover and the access screws for R419.
b. Connect the output of the LFSSG to the OUT MOD
DVM using a BNC tee.
Program the OU T to RCL 98, then program the O UT to 350 M Hz, 7 dBm,
c.
and EXT AM at 90% AM depth.
d. Program the LFSSG for l kH z and a voltage of0.7071 V rms, as measured
by the DVM.
e. Connect the OUT R F OUTPUT connector to the M odulation Analyzer R F
input.
f. Program the M odulation Analyzer to measure + Peak A M in a 0.3-kHz to
1 5-kHz bandwidth.
m
g. Note the easured AM depth reading with the M odulation Analyzer.
h. Turn off the OUT EXT A M control and turn on the !NT A M control.
1.
Program the OUT for 1000-Hz modulation frequency.
J .
Adjust R419 for an AM depth equal t o that noted i n step g.
!NT
k. Turn off the OUT
g
nal as measured with the M odulation
AM control.
e
m
g the bottom
I N
connector and the
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