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SPP-M937
5-1. BLOCK DIAGRAM – BASE UNIT SECTION (1/2) –
BASE RF BOARD
ANT1
(ANTENNA)
ANT
EEPROM
U4
DI
3
CLK
2
DO
4
CS
1
47
45
46
44
43
02
SECTION 5
DIAGRAMS
RX AUDIO
TX AUDIO
LED6
CHARGE
LED1
LED3
LINE 1
INTERCOM
OSC
Q22
X1
4MHz
LED1
LED6
LED3
2
3
21
73
74
75
ROW0 – ROW5
COL0 – COL3
65-70
61-64
KEY MATRIX
(SEET KEY)
– 17–
BUFFER
2
1
U9 (1/2)
6
ATTENUATOR
Q1
LOW-PASS FILTER
U9 (2/2)
7
LED4
MUTING
LED2
LINE 2
BACKUP B+
LED4
LED2
76
77
19
28
12 11
10 9
24
S2, 3
S1
RINGER LEVEL
DIAL MODE
TONE
PULSE
FIL2
EXP
FIL2
PRE
OUT
OUT
IN
IN
EXPANDER
2
1
23
20
CIRCUIT
LOW-PASS
PREAMP
FILTER
COMPRESSOR, EXPANDER, NOISE GATE
U6
LOW-PASS
FILTER
COMP
FIL1
FIL1
OUT
OUT
IN
BUFFER
COMPRESSOR
+
3
4
1
2
5
U14 (1/4)
CIRCUIT
COMP
MUTE
6
16
29
20
26
SYSTEM CONTROLLER
U2 (1/2)
– 18 –
• SIGNAL PATH
: RX
: TX
RO1
(Page 19)
RIN
OUT
BUFFER
+
A
19
18
6
7
U14 (2/4)
RO1 AMP
MIC
MIC
(Page 19)
AMP
NF
BUFFER
+
B
10
8
9
U14 (3/4)
EXP
MUTE
15
DTMF TONE
GENERATOR
U11
14
TONE
OUT
OSC IN
6
OSC OUT
7
X2
3.58MHz
D0 – D3
TEN
9 – 12
2
25
57 – 60
56
D0 – D3
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