4-3
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).
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.
LPF
LPF
HPF
HPF
AMP
LPF
AMP
LPF
R_DDET
L_DDET
CODEC
LINEAR
DSP
IC400
IC402
DIGI/AN
AFMUTE
IC111
AFMUTE
DIGI/AN
IC111
L_DAF
R_DAF
IC407
IC407
IC406
IC406
L_DAF
R_DAF
IC407
IC406
AF
AMP
SP1
AF
AMP
J102
J101
[SP2]
[SP1]
AFSW
SP
MUTE
VR
ELEC.
MUTE
SP
SP
MUTE
A band AF
B band AF
IC106
Q106
IC105
Q104
Q105
IC109
IC110
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).
D/A
LPF
HPF
J100
1
2
3
4
5
6
7
8
ALC
AMP
LPF
IDC
D/A
A/D
MIC
AMP
BUFF
ATT
MUTE
SW
MIC
FM
FM
DV
DV
BTMIC
SW
Audio Processor LSI
BTMIC
SELECT
MODE
DSP
IC307
IC100
IC100
IC102
IC103
IC104
IC104
IC400
IC103
IC103
• DIGITAL DEMODULATION CIRCUIT
• RX AF CIRCUITS
• TX AF CIRCUIT
