3-5
3-2 TRANSMITTER CIRCUITS
TX AF CIRCUIT (MAIN UNIT)
The audio signal from the microphone (MIC signal) is applied
to the MAIN UNIT, through the MICROPHONE CONNECTOR
(MIC UNIT: J1), and then amplifi ed by the MIC AMP (IC141).
The amplifi ed signal is applied to the AF AMP (IC5163),
through the LPF (IC5161).
The audio signal from the accessory socket [ACC] on the
rear panel, is passed through the MIC line SWs (IC5211 and
IC5212), TX/RX AF SW (IC5213) and LPF (IC5161), and
then applied to the AF AMP (IC5162).
The amplifi ed signal is applied to the A/D converter (IC5071)
and converted into a digital audio signal.
The converted digital audio signal is applied to the DSP (Ana-
log mode: IC5001 or DV mode: IC5502), and demodulated
and processed. The demodulated signal is applied to the D/A
converter (IC5071), converted into the 36 kHz 3rd TX IF sig-
nal, and then amplifi ed by the active LPF (IC5081).
The amplifi ed 3rd TX IF signal is applied to the 3rd TX IF cir-
cuit, through the 3rd TX IF SW (IC5111).
1
2
3
4
5
6
7
8
MIC
AF
AMP
D/A
TX IF
MIC
AM P
A/D
IF
AM P
J1304
1
2
3
4
5
6
7
8
LPF
LPF
DISPLAY UNIT
MIC
DV-DSP
IF-DSP
36kHz
IC141
IC5111
IC5081
IC5081
IC5161
IC5071
IC5502
IC5001
MAIN UNIT
IC5163
IF
AMP
BPF
XTAL
FI4101
D4301,D4302
PIN
D4053,D4054
ATT
2LO
BW:15kHz
124.032MHz
f0=124.487MHz
To the 1st TX IF circuit
From the 3rd TX IF circuit
Q4251
TX IF
124.487 MHz
IF
AM P
BPF
CERAMIC
DIPLEXER
2nd RX IF circuit
BW=20kHz
419kHz
3LO
To the 2nd TX IF circuit
From the TX AF circuit
FI4351
IC4351
IC4501
IC4502
IC4503
Q4401
MAIN UNIT
TX IF
455 kHz
3RD TX IF CIRCUIT (MAIN UNIT)
The 3rd TX IF signal from the modulation circuit is applied
to the 3rd TX mixer (IC4502), through the TX/RX 2nd IF SW
(IC4501), mixed with the 419 kHz 3rd TX LO signal, resulting
in the 455 kHz 2nd TX IF signal.
The converted 2nd TX IF signal is applied to the 2nd TX IF
AMP (Q4401) through another 2nd IF SW (IC4503). The am-
plifi ed signal is applied to the 2nd IF fi lter (FI4351), through
the 2nd IF SW (IC4351), to remove unwanted signals.
The fi ltered 2nd TX IF signal is applied to the 2nd TX IF
circuit, through the diplexer (L4304, L4351, L4352, C4302,
C4303, C4351).
2ND TX IF CIRCUIT (MAIN UNIT)
The 2nd , from the 3rd TX IF circuit is applied to the 2nd IF
mixer (D4301 and D4302), then mixed with the 124.032 MHz
2nd TX LO signal, resulting in the 124.487 MHz 1st TX IF
signal.
The converted 2nd TX IF signal is amplifi ed by the 1st TX IF
AMP (Q4251), passed through the 1st IF fi lter (FI4101) to
remove unwanted signals, and then to the variable attenuator
(D4053 and D4054) to adjust the signal level.
The level-adjusted 1st TX IF signal is applied to the 1st TX
IF circuit.
• TX AF CIRCUIT
• 2nd TX IF CIRCUIT
• 3rd TX IF CIRCUIT
