Icom IC-F4029SDR, Service Manual

Page: 24 / 48

4 - 5
CPU5V
regurator
+5V
regurator
S5V
regurator
T5V
regurator
R5V
regurator
Power switch
R315
F701
(PA-C unit)
Q26–Q28
IC17
Q23
Q24, Q49
Q25
VCC
CPU5
CPU
+5V
S5V
“S5C”
“PWON”
Voltage line
Control signal
8
22
87
88
“T5C”
“R5C”
T5V
LED backlight driver (Q45),
LCD driver (IC20),
D/A converter (IC12), etc.
CPU (IC22),
EEPROM (IC10),
Reset IC (IC8), etc.
Drive amplifier (Q702),
Power amplifier (Q701), etc.
PLL IC (IC2),
VCO’s, etc.
Transmit circuits
Receive circuits
R5V
(IC22)
Battery pack
4-5 POWER SUPPLY CIRCUITS
Voltage from the attached battery pack is routed to whole of the circuit in the transceiver via a switch and regulators.
4-4 DIGITAL CIRCUITS (DSP UNIT)
4-4-1 RECEIVING
The 450 kHz 2nd IF signal from the IF IC (MAIN-C UNIT;
IC9, pin 11) is applied to the DSP unit via the buffer (MAIN-C
UNIT; Q8). The applied 2nd IF signal is passed through the
anti-aliasing filter (FI1) to remove unwanted components.
The filtered 2nd IF signal is amplified at the IF amplifier
(IC7, pins 1, 3), and applied to the A/D converter (IC13,
pin 3) and converted into the digital IF data. The converted
digital IF data is applied to the DSP IC (IC10) as a clock
synchronizer digital signal.
The digital-processed digital audio signal from the DSP IC
(IC10) is applied to the linear codec (IC16) and converted
into the analog audio signals, then applied to the AF mixer
(MAIN-C UNIT; Q36, Q37).
4-4-2 TRANSMITTING
The MIC signals from the AF mixer (MAIN-C UNIT; IC5, pin 7)
are applied to the linear codec (IC16, pin 2) and converted
into the digital audio data. The converted digital audio data
is applied to the DSP IC (IC10).
The processed digital audio signal from the DSP IC (IC10)
is applied to the linear codec (IC16) again, then converted
into the GMSK base band signal. The converted base band
signal is passed through the two-staged LPF (IC8, pins 6, 7
and pins 1, 3) and TX switch (IC9, pins 1, 2), then applied to
the D/A converter (MAIN-C UNIT; IC12, pin 9) via the buffer
amplifier (MAIN-C UNIT; IC7, pins 6, 7).
BPF
From FM IF IC
(IC9, pin 11)
To AF cricuits
From
Analog switch
(IC3)
To D/A converter
(IC12, pin 9)
• DIGITAL CIRCUITS BLOCK DIAGRAM
DSP UNIT
Buffer
AMP
AMP
Q18
RECEIVED SIGNAL
FI1
IC7
IC13
IC10 IC16
IC8
IC8
Q36, Q37
AMP
IC7
A/D
LINER
CODEC
IC
AF
MIXER
DSP
IC
IC9
TX SW
LPF
IC5
AF
MIX
TRANSMIT SIGNA
+5V
regurator
IC1
+3.3VA
regurator
+3.3V_A
+5V
+3.3V_VDD
+1.35V_VDD
IC4
VCC
+3.3V
regurator
IC2
DC-DC
1.35V
IC3, D1
• MAIN-C UNIT
• DSP UNIT