Transmit Circuits; Digital Demodulation Circuit (Main Unit); Rx Af Circuit (Main Unit); Tx Af Circuit (Main Unit) - Icom ID-5100E Service Manual

DIGITAL DEMODULATION CIRCUIT (MAIN UNIT)

While operating in the DV mode, the demodulated signal (dig-
ital audio signal) is passed through the LPF (Band A: R1195,
R1206, C1461 and C1475/Band B: R1194, R1205, C1460
and C1474) and amplifi ed by the AF AMP (Band A: IC407/
Band B: IC406). The amplifi ed signal is applied to the liner
codec (IC402) to be converted into the digital audio signal.
The digital audio signal is demodulated by the DSP (IC400),
and then applied to the linear codec (IC402) again, to be de-
coded into an analog audio signal.
The decoded AF signal is applied to the RX AF circuit, through
the HPF (Band A: IC407/Band B: IC406) and LPF (Band A:
IC407/Band B: IC406) and AF SW (IC111).
• DIGITAL DEMODULATION CIRCUIT
IC400
DSP
IC407
AMP
L_DAF
LINEAR
R_DAF
CODEC IC406
IC402
AMP
IC407
HPF
IC406
HPF

RX AF CIRCUIT (MAIN UNIT)

The demodulated AF signal from the AF SW (IC111) is ap-
plied to the electric volume (IC110), which separately adjusts
the A and B bands AF signal in level. The level-adjusted AF
signal is passed through the AF line SW (IC109).
When the AF signal is output from the internal speaker
or [SP1] jack:
The AF signal is passed through two speaker mute SWs
(Q105 and Q104), and then amplifi ed by the AF power AMP
(IC105).
The amplifi ed AF signal is output to the internal speaker
(CHASSIS: SP1) or external speaker, through the [SP1] jack
(J101).
When the AF signal is output from the [SP2] jack:
The AF signal is passed through the speaker mute SW
(Q106), and then amplifi ed by the AF power AMP (IC106).
The amplifi ed AF signal is applied to the [SP2] jack (J102).
• RX AF CIRCUITS
IC105 Q104 Q105
[SP1]
AF SP
AMP MUTE MUTE
J101
SP1
IC106 Q106
[SP2]
AF
AMP MUTE
J102
L_DDET
LPF
R_DDET
LPF
IC407
IC111
L_DAF
DIGI/AN
LPF
AFMUTE
IC111
IC406
R_DAF
DIGI/AN
LPF
AFMUTE
SP
IC109 IC110
A band AF
ELEC.
AFSW
B band AF
VR
SP

4-2 TRANSMIT CIRCUITS

TX AF CIRCUIT (MAIN UNIT)

The AF signal from the microphone (MIC signal) is passed
through the MIC SW (IC100) and ATT (IC100), and then ap-
plied to the MIC AMP (IC102).
The amplifi ed signal is applied to the audio processor LSI
(IC103), through the mute SW (IC104).
The audio processor LSI contains 16-bit liner CODEC, MIC
AMP, audio fi lters, D/A converter, and so on.
• When operating in the DV mode
The applied signal is further amplifi ed by the ALC AMP. The
amplifi ed signal is applied to the liner CODEC, to be encoded
into a digital audio signal.
The digital audio signal is processed by the DSP (IC400), and
then passed through the mode SW (IC104) and LPF (IC103),
and then applied to the D/A converter (IC103), to be adjusted
in level.
• When operating in the FM/FM-N mode
The applied signal is passed through the HPF (IC103), IDC
(IC103), LPF (IC103), mode SW (IC104) and LPF (IC103),
and then applied to the D/A converter (IC103) to be adjusted
in level.
The level-adjusted signal is applied to the modulation circuit.
• TX AF CIRCUIT
IC307
BTMIC
BUFF
IC100 IC100
J100
BTMIC
ATT
1
SW
2
3
4
5
MIC 6
7
8
IC103 Audio Processor LSI
FM
HPF
DV
ALC
AMP
4-3
IC102
IC104
MIC MUTE
AMP
SW
IC104 IC103
IC103
FM
IDC LPF
MODE
LPF D/A
DV
SELECT
A/D D/A
DSP
IC400