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5.3
CAR-AVR_
(Carrier/Automatic Voltage Regulator)
BOARD
(X50-1030-10)' (See Figure 14)
CARRIER
OSCILLATOR
This
crystal-controlled
oscillator produces
a carrier signal
during
transmission
and
acts
as the
BFO
for
balanced
product detection during reception. The circuit uses a diode
switch for frequency switching.
AVR (See figure 14)
The automatic voltage regulator circuit detects a reference
voltage
across
the
IC
module
to
control
the
output
transistor, Q6, to deliver stable 9 volt power to the load.
The IC and output transistor are protected from a shorted
output by a circuit consisting of Q3, Q4 and O5.
SWITCHING
CIRCUIT
The board. also holds a TDB/RDB switch to transfer signals
between the transmit and receive circuits.
TC3
VRI
TC4
Q7
Q3.
Qt
Qs
Ti
Qs
Qe
FIGURE
14,
CAR-AVR
Board
POWER
sup)
PRLEBLY
CONNECTOR
UNREG,
14V
REG 9V
YY
Ral isk L8 ImH RI 47K
Qo
Qio
3394,I5KH2
Xi
il
K
Tel 20P
3395,0KHz
X2
(2 imH year
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Te2 20°
R3 47K
L3ImH
$
LAL
3397.125KH2
x3
8
ye
Qie2
EQi
Egi
|
|
Qs
33)
39}
(KI-3)
14v
ONS erry KEY uack
+ 28C460(B)
1280 234(0)
:MFC4060A
2SC374(BL)
1 28C736(Y)
1981555
: VO6B
Larries Gn
OUT output P17
GND
SC 373
SA495
CAR—AVR Unit (X50-1030-10)
FIGURE
15.
CAR-AVR
Schematic
24
TPI
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