Midland Radio SP-300 - Manual (Page 50)

PAGE -47-
May 2001 Block Diagram
REVISIONS
CHG BY DATE
DESCRIPTION DESCRIPTION
RELEASED TO MANUFACTURING
REV
A DGC 03/01
TITLE
SCALE SHEET OF
SIZE DOCUMENT
NUMBER B
1 1 NA
SP-300 Series
SYSTEM ELECTRICAL
BLOCK DIAGRAM
060-***-****
LEVEL SHFTER
Q6,7,8,11
TCXO1
FRONT END
R
V
C21,C22
REF L.P.F.
Q202/203
TX VCO
CONT
TX VCO
Q16/Q17
TX 5V
TX BUFFER
P.A. MODULE
Q501 Q502 Q503
L.P.F.
ANT SW ANT
D5
D6
TX B+
FILTER
RX
5V
Q60
LOW NOISE AMP FILTER T2/3/D9
MIXER
XF1
1st IF FILTER
45.1MHz
1st IF AMP
CURRENT SENSOR
V Batt
Q22
CONTROL
IC3B
RV3
POWER ADJUST
LOW
FROM CPU
RV1
POWER ADJUST
HI
IC3A
CURRENT DETECTOR
LOCAL LPF
L1,L2 Q12
RX BUFFER
CONT
Q302/303
RX VCO
MOD
IC2
PLL CIRCUIT
L/D
PLL EN
DATA
CPU
Q5
INVERTER
DC/DC CONVERTER
16V
F in
B+
Ref Freq
TCXO
TCXO (12.8MHz)
TCXO MOD
+5V
BALANCE
RV401
BUFFER
IC401A
1 2
1
3
TX B+
IC405B IC406B
RV403
SUB AUDIO LEVEL
IC411
14053 X
6TH LPF
IC407 MF6
IC407 IC406C
2ND LPF 2ND LPF
IC407
14503 Y
R478,479,480
CTCSS/DCS
ENCODE
IC406A
2ND
LPF
Q25 MIXER
INPUT
IC5 IF IC
MUTE
RX +5V
AF OUT FIL IN FIL OUT
MUTE
SQ IN
QUADRATURE
T1
X1
2nd LOCAL
44.645MHz
25KHz BAND PASS
CF1
455KHz
12.5KHz BAND PASS
CF2
455KHz
Q24
INVERTER
L16/C111
NOISE FILTER
RV2
SQ LEVEL
Q27
NOISE AMP Q26
FAST
INTEGRATER
RX +5V
R451/C471
DEMPHASIS
IC402
4 3
5
AF LEVEL
VR3
CPU AF MUTE
IC6
LM386
AUDIO AMP
IC410
300HZ HPF
IC404C/D
TX AF AMP
RV402
TX MOD LEVEL IC 404A/B
3KHz LPF
SPLITTER FILTER
IC411
14503 Z
CON701
+7.5V
GND
MIC
SPK
1
2
3
4
5
6
7
8
9
10
11
12
12PIN
MIC1
SP1
D15
CHARGE
V Batt
FUSE VCC
D16
REVERS PROTECTOR
VCC 5V REGULATOR
IC1
5V
TX/RX INDICATION
LED1
DUAL COLOR
CH SEL
Q404/405
LED
DRIVER
VCC
Q403/417
LOW BATT
DETECTOR MON
PTT
OPTION
L/D
CHANNEL
LED
CONT
LOW BATT
IC409
CPU
CALL DET
IC408
EEPROM
Q410
RESET
386 EN ALERT BUSY
X401
3.57
SUB AUDIO
ENCODE