Fluke 6060B Instruction Manual page 138

MAINTENANCE
CALIBRATION
ADJUSTMENTS
d.
Adjust
R309
for
an
indication of
+0
mV ±
0.5
mV.
e.
Program
the
UUT RF OUTPUT
to
ON.
f.
Replace
the access screws.
2.
Modulation
Oscillator Level
Adjustment
This adjustment
sets
the
modulation
oscillator
level.
TEST
EQUIPMENT
Modulation 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 the
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
1-volt
peak
external
modulation
signal as measured with the
Modulation
Analyzer.
a.
Gain
access to the access
screws
for
R419
by removing
the
bottom
instrument cover and
the access
screws
for
R419.
b.
Connect
the
output of
the
LFSSG
to the
UUT
MOD
IN connector and the
DVM
using a
BNC
tee.
c.
Program
the
UUT
to
RCL98,
then program
the
UUT
to
350
MHz,
7
dBm,
and
EXT
AM
at
90%
AM
depth.
d.
Program
the
LFSSG
for
1
kHz
and
a voltage
of0.7071V
rms, as
measured
by the
DVM.
e.
Connect
the
UUT RF OUTPUT
connector
to the
Modulation
Analyzer
RF
input.
f.
Program
the
Modulation Analyzer
to
measure
+
Peak
AM
in
a
0.3-kHz
to
15-kHz bandwidth.
g.
Note
the
measured
AM
depth
reading with
the
Modulation
Analyzer.
h.
Turn
off the
UUT EXT
AM
control
and
turn
on
the
INT
AM
control.
i.
Program
the
UUT
for
1000-Hz modulation
frequency.
j.
Adjust
R419
for
an
AM
depth equal
to that
noted
in
step
g.
k.
Turn
off the
UUT
INT
AM
control.
f
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4C-6
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