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9.3
MPX
SECTION
1. Through 300 ohm
dummy antenna,
connect
FM signal
generator
to 300 ohm FM
antenna
terminals.
2.
Connect multiplex
signal
generator
to extemal
modulation
terminals
of
FM
signal
generator.
3. Connect oscilloscope
horizontal input
to
MPX
signal
pilot
output
and
vertical
input via
probe
to TP
(No.
13) of circuit board.
sx-450
4.
Set SX-450 dial
indication
to 98MHz
and adjust
FM signal
generator
for center
of scale indi-
cation
on AM/FM
meter.
5. With
FM
signal
generator
unmodulated,
adjust
VR1 so that lissajous
pattern
on oscilloscope
becomes
stationary
as shown
in Fig. 12.
6.
With MPX signal
generator
modulation lkHz,
L
+
R
67.5kHz
deviation and
pilot
7.5kHz
deviation,
adjust T4 for minimum distortion.
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AC voltmeter
Distortion
meter
FM
signal
generator
Dummy load
Oscilloscope
MPX
signal
generator
Fig.12