Codan Radio Communications VT-3-150-SN User Manual
ELECTRONICS LTD.
DANIELS
TM
Audio Processor Board Instruction Manual
9-15
9.12
AM Audio Processor Schematic Diagram
Micropho ne Input
Leve l Adjust
Leve l Adjust
Micropho ne
Automati c Modulati ons
Co ntrol Input Adjust
Co ntrol Input Adjust
Balanced Input
Level Adjust
Level Adjust
Modulation Co ntro l
Outpu t Adjust
AM C B yp ass
Mod o utput
B alanced Input
9.5 Vdc
13.8 Vdc
Automatic Modulatio n C o ntro l
OPTIONAL
Auto ma ti c Le ve l Co n tr o l
X
Y
X
Y
X
Y
X
Y
X
Y
3.0 KHZ BESSEL LOW PASS FILTER
3.0 KHZ BU TTERWORTH LOW PASS FIILTER
App ro x. 200mV rms @ 90% mod.
A LC B y p ass
FB1
4.7nF
C1
CW
5K0
R1
TP1
470nF
C2
CW
50K0
R4
TP2
Vcc
Rect In
Var G
Rect Cap
Output
Inv In
R3
THD
Trim
Trim
GND
2
3
1
7
5
6
8
13
4
SA571D
U1a
Rect In
Var G
Rect Cap
Output
Inv In
R3
THD
Trim
Trim
15
14
16
10
12
11
9
SA571D
U1 b
100K0
R6
TP3
680nF
C3
100nF
C6
10nF
C7
TP4
C8
680nF
680nF
C9
4.7uF
4.7uF
C10
470nF
470nF
R13
18K2
18K2
CW
5K0
R16
4.7uF
C12
1.0nF
C13
R18
470K0
470K0
TP5
TP6
4.7uF
C21
TP8
MT-3 TX TIME-OUT-TIMER
3
P1
2
P5
1
P1
2
P1
3
P2
4
P1
4
P3
4
P5
4
P2
1
P3
8.0V
9.5V
8.0V
P7 -1
P8 -1
P9 -1
P6 -1
J7-1
J8 -1
J6 -1
J5 -1
1N5221B
D1
1N5221B
D2
681R0
R27
2.2uF
C11
TP7
30K9
R5
2
P3
2
3
4
1
11
U2
MC33174
MC33174
a
6
5
7
U2
MC33174
MC33174
b
9
10
8
U2
MC33174
MC33174
c
8.0V
R3
49K9
49K9
R15
49K9
49K9
C14
100nF
100nF
C16
2.2nF
2.2nF
13
12
14
d
MC33174
U2
100K0
R14
470nF
C5
R17
10K0
10K0
C15
4.7nF
4.7nF
R32
51K1
51K1
C18
220pF
220pF
R29
5K11
5K11
R19
5K11
5K11
R24
15K4
15K4
R31
15K4
15K4
R23
51K1
51K1
R28
82K5
82K5
C22
680pF
680pF
C23
220pF
220pF
JU5
R25
82K5
82K5
JU7
JU8
39K2
R20
47K5
R30
330pF
C17
150pF
C25
20K0
R2
220pF
C20
JU6
3K48
R22
JU4
1.0uF
C19
10K0
R9
27K4
R10
27K4
R11
3M30
R26
JU3
JU9
4K75
R8
1K2
R7
JU2
JU1