Fluke 6060B Instruction Manual page 145

MAINTENANCE
CALIBRATION
ADJUSTMENTS
2.
FM
Adjustments, R82, R90,
AND
R87
TEST
EQUIPMENT
Modulation Analyzer
LFSSG
DVM
REMARKS
The
FM
Cal adjustment,
R82,
sets
the overall deviation accuracy,
whereas the
Low-Rate
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.
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,
R90,
and
R87,
respectively.
a.
Remove
the
instrument cover
and
the
FM
CAL,
FM
flatness,
and
Low-
Rate Deviation adjustment
access screws
from
the
cover of the
module
plate.
b.
Connect
the
output of the
LFSSG
to the
UUT
MOD
IN connector
and
to
the
DVM'
using a
BNC
tee.
c.
Connect the
UUT RF OUTPUT
to the
Modulation Analyzer
input.
d.
Program
the
M
odulation
Analyzer to
measure
FM
+
peak
in
a
0.05-kHz to
>
200-kHz bandwidth.
e.
Program
the
UUT
to the
[RCL]
[9][8].
Then program
the
UUT
to 3S5.5-
MHz,
7
dBm,
EXT FM,
99.9-kHz
deviation.
f.
Program the
LFSSG
to
1
0
kHz
and
0.707
1
V
rms
as
measured by the
DVM.
g.
Adjust
R82
for 100.0
kHz,
as
measured by
the
Modulation Analyzer.
h.
Program
the
LFSSG
to 0.4
kHz
and
0.7071V
rms, as
measured by
the
DVM.
i.
Adjust R90,
the low-rate deviation for 100.0
kHz,
as
measured on
the
Modulation Analyzer.
j.
Program
the
LFSSG
to
1
kHz, and adjust
R87
for 100.0
kHz
as
measured
on
the
Modulation Analyzer.
k.
Repeat
steps
f
through
j
until
the deviation flatness
is
100.0
kHz
±
0.3
kHz.
l.
Turn
the
UUT EXT
FM
off,
and note
the
Modulation
Analyzer peak
deviation (noise) reading.
m. Turn the
UUT EXT
FM
on.
4C-13