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OT-12HS/HR/HB/HY/BL
OT-12ES/ER/EB/EY
THE
INSTRUCTION
OF
FREQUENCY
ADJUSTMENT
In order to comply with FTZ rule: Nr. 478/1981, please fix the
low end of dial frequency (87.5MHz) and the high end of dial
frequency
(107.9MHz)
on FM band, by adjusting oscillation
coils (L3) and oscillation trimmer (TC2), respectively, as illust-
rated in Figure 12—1.
FM IF/RF ADJUSTMENT
@
Set the signal generator to produce a signal of 400Hz, 30%,
FM modulated.
@ For adjustment in step 1, see |Note B].
IF (Connect instruments as shown in Fig. 12—2.)
TEST | FRE-
| DIAL | AD-
STEP|
BAND | STA-
|QUEN- | SET-
|JUST-
GE
CY
| TING
|MENT
High
Adjust for
FM
Heat end of
uy
best 'S"
z
dial
curve.
RF (Connect instruments as shown in Fig. 12—3.)
Adjust for
maximum
output.
Repeat steps 2, 3, 4 and 5 until no further improvement
can be made.
FM STEREO
ADJUSTMENT
@
Set the Band Selector (SW1) to "FM" position and Mode
Selector Switch (SW104) to "STEREO" position.
@
Before this adjustment, connect the anode side of Stereo
Indicator (D107) to GND.
@
Connect instruments as shown in Fig. 12—4 and Fig. 12—5.
ADJUST-
MENT
DIAL
POINTER
FREQUENCY
98MHz (54dB)
unmodulated
Adjust for
38 +0.1kHz
When
other
ceramic
filters than
the one
(red) having the
central frequency of 10.7 MHz are used, note that a marker
(10.7 MHz) of FM sweep generator, if used, will be deviated —
therefore,
adjust the generator
by putting off the marker.
Blue | 10.67 MHz 30KH2 |
[Red | 10.70 MHz? 30kH2 |
Central
frequency (fo)
a
(OD etc © |
Tc4@
oom
IS}
Figure 12—1
ge
ee
ee
OSCILLOSCOPE
CURVE
FM SWEEP GENERATOR
Rod Antenna
ICs.
aA,
Figure 12—2
eens
ELECTRONIC
VOLTMETER
FMSIGNAL (See Figure 12—5)Rod Antenna
GENERATOR
Figure 12—3
FM
STEREO
Telescopic
1C3
FREQUENCY
SIGNAL
GENERATOR
Rod Antenna
@ pin
1000PF
COUNTER
Sn pS
(See Figure 12-5)
DUMMY
Figure 12-4
R1
To Telescopic Rod Antenna
R1 = 37.5 ohm
Z=75 ohm << R2= 78 ohm
R1 = 50 ohm
Z = 50 ohm
Ao = coohm
To Chassis GND
Z: Output impedance of signal generator
Figure 12-5
FM
DUMMY
vy Color Mark
3
2
1
Figure 12-6
1. Input
2. GND
3. Output
=e
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