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(7)
Set the
FA/\/0M
switch
to
EXT
and
the
METER
switch
to
FM/0M.
(8)
Select
128-256
MHz
range
and
tune
the
UUT
to
270MHz.
(
9
)
Connect
the
audio (1kHz)
signal
generator
to
the
FM/0M
EXT
socket
and connect
the mi
Ili
voltmeter
to
monitor
this
audio
input.
Adjust the audio source
for
1
.00V
r.m.s. input
level.
(10)
Connect
a modulation
meter
to
the
50Q
output
of
the
UUT.
(IT)
Observe
the
modulation meter
and
adjust the
front
panel
F/V\/0M
COARSE
adjust control
to
give
100kHz
peak
deviation,
±1%.
(12)
Adjust
R85 on p.c.b. 19-0844
to
give
1
00kHz
peak
deviation
I
indication
on
UUT
meter.
('jg)
Operate
the
PEAK
DEVIATION
switch
on
the
UUT
and
verify that
30kHz
(±3%) 10kHz
(±3%)
and
3kHz
(±3%)
deviations are
observed on
the
modulation meter
for
the
corresponding
positions
on
the
PEAK
DEVIATION
switch
.
(14)
Disconnect
the
test
equipment.
Check
that
all
p.c.b.
assemblies are
tightly
screwed
down.
Replace
the casting covers,
checking
carefully that the
r.f.
gasket
is
correctly positioned
and
not
damaged.
Screw
the covers
down
tightly,
but
avoid
using excessive force
which
might
strip
the threads.
DISTORTION
CHECK
5.17
Test
Equipment Required
Page 5-2
Table 5
Spectrum Analyser
Item
5
5.18
Procedure
(1)
Set the
UUT
controls as follows:-
OUTPUT
switch
to
NORMAL.
OUTPUT
LEVEL
control
to
OdBm
position.
RANGE MHz
switch
to
'256
-
512'
position.
FM/J3M
and
AM
INT/EXT
switches
to
OFF
METER
switch
to
CW
position.
Tune
the
UUT
to
250MHz
and
adjust the
VERNIER
control
for
OdBm
reading
on
the
UUT
meter.
5-15
9081
&
9082
Vo
1.2.
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