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INTERNAL BLOCK DIAGRAM OF ICs
■
LA1831
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24
ALC
BUFF
LEVEL
DET
AM/FM
IF
BUFF
AM/FM
SW
STEREO
SW
PILOT
DET
S-CURVE
FM
IF
FM
DET
TUNING
DRIVE
REG
GND
VCC
VCO
FF FF
DECODER
MUTE
TRIG
STEREO DRIVE
FF
PHASE DET
FM
AM
COMP
AM
OSC
AM
MIX
AM
RF-AMP
AM
DET
AM
IF
AGC
23 22 21 20 19 18 17 16 15 14 13
Pre Out
Ch2
3.3µF
3.3µF
3.3µF
3.3µF
3.3µF
1000µF
1000µF
47µF
47µF
47µF
0.018µF
1000µF
3.3µF
47µF
1.2µF
100
µF
R . R
Vcc
1000
µF
47µF
0.018µF
10kΩ
10kΩ
150kΩ
150kΩ
1MΩ
2.2kΩ
2.2kΩ
Rec IN
Ch2
Rec
IN
Rec IN
Ch1
ALC
Rec Out
Ch2
180kΩ
180kΩ
Gv
Gvo
180kΩ
180kΩ
1kΩ
1kΩ
1kΩ
1kΩ
100kΩ
100Ω
10kΩ
10kΩ
10Ω
300kΩ
9.1kΩ
100Ω
Pre IN
Ch2/B
(Play Rec)
Pre IN
Ch2/A
(Play only)
Pre IN
Ch1/B
(Play Rec)
Pre Out
Ch1
Pre IN
Ch1/A
Ch1/B
NF
Ch2/A
Ch1/A
Ch1/B
Gvo
Gv
Gvo
Gv
Vcc
M
N
NF
NF
Ch1
Ch1
Ch2
Gvc
GV
Ch2
ALC
GND
Rec
15
14
13
12
11
23
24
1
2
161718192122
IN
Vref1
Vref
Vref2
A/B
Metal
Out
Pre
Out
REC
Out
Rec Out
Ch1
Mix
Out
GND1 M/N
6.8kΩ
A
B
1000pF
1000pF
6.8kΩ
9.1kΩ
20
10 9876435
M/N
L-IN1
100K
100K
100K
100K
100K
100K
100K
100K
48918
27
21
22
20
26
24
25
LOUT
SCL
SDA
DIG_GND
ROUT
V
S
AGND
R
B
R
B
14 15
10 11 19 12 13 23
5
G
G
6
7
3
2
INPUT MULTIPLEXER
+GAIN
MUXOUTR INR TREBLE(R) BIN(R) BOUT(R) CREF D98AU883
0/30dB
2dB STEP
MUXOUTL
VOLUME TREBLE
I CBUS DECODER + LATCHES
BASS
SPKR ATT
LEFT
VOLUME TREBLE BASS
SUPPLY
V
REF
SPKR ATT
RIGHT
INL TREBLE(L) BOUT(L)BIN(L)
1
28
L-IN2
L-IN3
L-IN4
R-IN1
R-IN2
R-IN3
R-IN4
2
1000
µF
1000
µF
100n
F
RL (R)
RL (L)
4.7
Ω
18K
OUT (R)
IN- (R)
IN- (L)
18K 4.7
Ω
100n
F
560
Ω
560
Ω
OUT (L)
4
8
10
2
6
-Vs
1
IN (R)
1
µF
+5V
15K 18K
GND
IN (L)
MUTE/
ST-BY
1
µF
1
µF
15K
+Vs
11
9
7
5
3
µP