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ICF-CD873L
6-2.
BLOCK DIAGRAM – TUNER Section –
MAIN BOARD (2/3)
ANT1
FM WIRE
ANTENNA
B.P.F.
BPF1
CT1, L1
L1
FM TRACKING
FM RF
CT2, L3-1
CT1
MW TRACKING
L3
MW/LW FERRITE-ROD
ANTENNA
L3-1
(MW)
CT2
L3-2
Q1
(LW)
(1/3)
CT3
VREF
CT3, L3-2
D4
CT4
Q1
(2/3)
LW TRACKING
MW/LW
LW FREQUENCY
SWITCHING
COVERAGE
• SIGNAL PATH
: FM
: MW/LW
05
FM/AM FRONT-END,
FM/AM DET, MPX
IC1
FM/AM
FM RF
IN
FE OUT
FM
18
16
FRONT-END
FM RF
20
D2
AM RF
IN
AM
19
FRONT-END
24
22
L2
L4
L4
D4
FM FREQUENCY
MW FREQUENCY
MW/LW
COVERAGE
COVERAGE
OSC
L2
FM OSC
CT4
D3
Q2
D4
MW/LW
(3/3)
SWITCHING
(FM/AM RF/OSC CIRCUIT)
LOW-PASS
VREF
FILTER
Q50, 51
11
12
FM/AM PLL
IC50
PD1
PHASE
MAIN CONTROL
15
DETECT
PRESCALLER
P2
P1
OUTPUT
CONTROL
P0
IF IN
I/O CONTROL
IF
REGISTER
COUNTER
2
1
5 4 3
X50
75kHz
– 15 –
CF3
10.7MHz
26
CF2
FM
10.7MHz
IF IN
FM IF AMP/
13
DISCRI
T1
TUNING
AM IF
INDICATOR
CF1
AM
450kHz
IF IN
AM IF AMP/
14
DET
PD1
STEREO/MONO
1/2
SELECT
CONTER
PD2
FM/AM
VCO
SELECT
REGULATOR
21
7
15
3
2
1
29
L.P.F.
VREF B+
B+
(5V)
10
8
7
9
L-CH OUT
TUNER L-CH
C
6
DECODER
R-CH OUT
TUNER R-CH
AMP
5
(Page 17)
TUN IND
12
SWITCH
ST IND
4
27
RV1
FM VCO
TUNER ON
D
(Page 17)
DATA, CLOCK, LATCH
B
(Page 14)
– 16 –
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