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WQ-272H(R)
FM IF/RF
ADJUSTMENT
SWITCH
POSITION
FM
mono
SIGNAL
400
Hz, 30%,
GENERATOR
TEST
FRE_
STEP
STAGE
QUENCY
1
IF
10.7
MHz
2
Detection
Repeat steps 1 and 2 until no further
3
be made.
87.3
MHz
4
Band
coverage
108.3
MHz
6
Repeat
steps 4 and 5 until
can
be made.
88
MHz
7
Tracking
8
108
MHz
9
Repeat steps 7 and 8 until no further
be made.
VCO
FREQUENCY
ADJUSTMENT
400 Hz, 30%, FM modulated
SIGNAL
GENERA-
(mono signal)
TOR
DIAL
FREQUENCY
POINTER
SETTING
FM mono position
98 MHz
98 MHz
at 60 dB
:
FM
modulated.
DIAL
POINTER
JUST-
REMARKS
SETTING
MENT
I . using a minus
driver,
the
core
T 2 counter-
clockwise
before taking
High
it out
frequency
bobbin.
2. Adjust
best
"IF"
curve.
Adjust
for
' 'S"
Curve.
improvement
can
Lowest
L3
frequency
Adjust for
maximal
Highest
TC2
output.
frequency
no further
imporvement
Adjust
for
88 MHz
1.2
maximal
108
MHz
TCI
output.
improvement
can
REMARKS
JUST.
MENT
FM stereo position
(unmodulated)
VRI
Adjust for
38.00
kHz
± 100 Hz.
10.7
MHz
FM Sweep
Generator
0.01 gF
turn
of
of the
10.7
for
Figure 14—2 FM IF CURVE
best
FM Signal
Generator
Dumm y
(See Figure 14—6)
FM Signal
Generator
Rod Antenna
GND
Dummy
(See Figure 14—6)
Figure 14—5 VCO FREQUENCY
— 14 —
IC3
ICl
O Pin
O Pin
unit
GND
GND
Figure 14—
1
FM IF
MHz
Figure 14—3 FM S CURVE
Rod
Antenna
IC3
O Pin
Unit
GND
GND
Figure 14—4
FM RF
IC3
Pin
1OOOpF
unit
300
kohms
RI
To Telescopic
To Chassis GND
RI
—37.5 ohms
Z = 75
=75ohms
RI
= 50 ohms
Z = 50ohms<
R2 = 50 ohms
Z: Output impedance of signal generator
Figure 14—6 FM DUMMY
Oscilloscope
10.7
MHz
Electronic
Voltmeter
o
Frequency
Coun
ter
Rod Antenna
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