— 20 —
3
6
11
2
5
8
1
4
14
15
12
9
10
16
13
7
FM IF AMP
LIMITER
AF/NULL
METER
QUADRATURE
DET
AF AMP
IF OFF
NULL METER
SHORTING
LEVEL
DET
METER
DRIVE
MUTING
CIRCUIT
DETUNE
DET
GND
B+
3
6
9
2
5
8
1
4
7
10
18
15
12
19
16
13
20
17
14
11
AM RF AMP
AM IF AMP
AM
MIXING
AGC
AM
OSC
GND
B+
(RF)
AM DET
METER
DRIVE
B+
(IF)
1
FM/AM SELECT
MUTING
FM/AM SELECT CONTROL
LOGIC / MUTE ON/OFF
MUTING
OUT
LAMP
DRIVE
PLL
GND
MPX
22
21 20 19 18 17 16
15
14
13
12
2
3
4
5
6
7
8
9
10
11
AM
+B
VCO
MUTE
ST
FM
L
R
FM/AM
1
2
3
4
REG
GND
CONTROL
REG
5
6
7
4-8. IC BLOCK DIAGRAMS (TUNER BOARD)
IC301 LA3401
IC901 LA5667
IC401 LA1245
IC221, IC251 LA1235
QUALITY BIT
GENERATOR
DEFFERENTIAL
DECODER
BIPHASE
SYMBOL
DECODER
OSCILLATOR
AND
DIVIDER
57kHz
BANDPASS
(8th ORDER)
CONTAS LOOP
VARIABLE AND
FIXED DIVIDER
REFERENCE
VOLTAGE
ANTI-
ALIASING
FILTER
CLOCKED
COMPARATOR
TEST LOGIC AND OUTPUT
SELECTOR SWITCH
RECONSTRUCTION
FILTER
14
15
16
13
12
11
10
9
3
2
1
4
5
6
7
8
CLOCK REGENERATION
AND SYNC
VP1
RDCL
TS7
OSCO
OSCI
V
DDD
V
SSD
TEST
TSTL
D
QUAL
RDDA
Vref
MUX
V
DDA
V
SSA
CIN
SCOUT
IC801 BU1992
