DEMODULATOR CIRCUITS (MAIN UNIT)
The 2nd RX IF signal from the 2nd RX IF circuits is passed
through the MAIN/SUB BAND SW (HF band; IC3501, VHF
band; IC3502, UHF band; IC3503), and then applied to the
demodulator circuits.
• MAIN BAND
The 2nd RX IF signal is passed through the AF SW (HF
band; IC3510, VHF band; IC3514, UHF band; IC3518), RX
mute SW (IC4604) and the balance-unbalance converter
(Balun; IC4602/IC4603), and then applied to the CODEC
(IC4651) to be converted into digital audio signal.
The converted digital audio signal is applied to the MAIN
DSP (IC4001), and demodulated and processed.
The demodulated signal is applied to another CODEC
(IC4461) to be converted into analog AF signal, and then
applied to the buffer amplifi er (IC4483).
The buffer amplifi ed AF signal is applied to the CONNECT UNIT.
3 - 4
AMP
IC4483
BUFF
IC4602
MUTE
IC4604
LPF
IC4603
LPF
IC4603
IC1201
IC1261
MAIN
CPU
CPLD
MAIN BAND PATH
SUB BAND PATH
CODEC
IC4461
IC4001
DSP
From the 2nd RX circuits
To the MAIN RX AF circuits
CODEC
IC4651
AMP
IC5481
CODEC
IC5451
IC5001
DSP
To the SUB RX AF circuits
CODEC
IC5451
VRIF
URIF
HRIF
IC3502
IC3503
IC3501
IC3514
IC35013
IC3518
IC3517
IC3509
IC3510
MAIN UNIT
MDRIF
From RF-B UNIT
From RF-B UNIT
From RF-A UNIT
MUTE
IC5404
BUFF
IC5402
LPF
IC5403
SDRIF
LPF
IC5403
From the modulator circuits
SP1
Internal
speaker
[MAIN EXT-SP]
[SUB EXT-SP]
VCA
AMP
IC301
IC201
SQ L
GATE
Q221
AMP
SQ L
GATE
Q231
Q321
SEL
SW
Q331
SEL
SW
IC201
AF
AM P
AF
AM P
IC351
RL361
VCA
RL371
AMP
IC221
AMP
IC221
BUFF
Q343
BUFF
Q344
IC341
IC342
J101
J102
RL372
SDRAF
MDRAF
CONNECT UNIT
J2(JACK UNIT)
[PHONES]
RX AF CIRCUITS (CONNECT UNIT)
• MAIN BAND
The AF signal from the demodulator circuits is applied to
the AF AMP (IC221), through the squelch gate (Q231).
The amplifi ed AF signal is applied to the Voltage Controlled
Amplifi er (VCA; IC301) to be adjusted in level (=audio output
level), through the AF SW (IC201) which toggles the AF
output lines for MAIN and SUB bands.
The level-adjusted AF signal is applied to the AF power AMP
(IC351), through the mute SW (Q321) and the buffer (Q343).
The amplified AF signal is passed through the AF mute
switch (RL361), and then applied to the internal speaker
through RL372, or external speaker jack ([MAIN EXT-
SP]; J101), or the amplified AF signal is applied to the
headphones jack (JACK BORD: J2).
• SUB BAND
The 2nd RX IF signal is passed through the AF SW (HF
band; IC3509, VHF band; IC3513, UHF band; IC3517), RX
mute SW (IC5404) and the balance-unbalance converter
(Balun; IC5402/IC5403), and then applied to the CODEC
(IC5451) to be converted into digital audio signal.
The converted digital audio signal is applied to the SUB DSP
(IC5001), and demodulated and processed.
The demodulated signal is applied to the CODEC (IC5481)
again, to be converted into analog AF signal, and then
applied to the buffer amplifi er (IC5481).
The buffer amplifi ed AF signal is applied to the CONNECT UNIT.
• SUB BAND
The AF signal from the demodulator circuits is applied to
the AF AMP (IC221), through the squelch gate (Q221).
The amplifi ed AF signal is applied to the Voltage Controlled
Amplifi er (VCA; IC301) to be adjusted in level (=audio output
level), through the AF SW (IC201) which toggles the AF
output lines for MAIN and SUB bands.
The level-adjusted AF signal is applied to the AF power AMP
(IC351), through the mute SW (Q331), the buffer (Q344) and
AF line SWs (IC341 and IC342), which selects the AF output
destinations from [MAIN EXT-SP] and [SUB EXT-SP].
The amplified AF signal is passed through the AF mute
switch (RL371), and then applied to the internal speaker
through RL372, or external speaker jack ([SUB EXT-
SP]; J101), or the amplified AF signal is applied to the
headphones jack (JACK BORD: J2).
• DEMODULATOR CIRCUITS
• RX AF CIRCUITS
