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3 - 4
3RD TX IF AND 2ND TX IF CIRCUITS (MAIN UNIT)
The 3rd TX IF signal from the modulation circuits is applied
to the 3rd TX mixer (IC3402) via the LPF (IC3401) to be
converted into the 2nd TX IF signal, by being mixed with
the 3rd TX LO signal from the PLL UNIT. The converted 2nd
TX IF signal is amplified by the IF AMP (Q3501), passed
though the one of 2nd TX fi lters (FI3501; for FM, AM mode
or FI3502; for SSB, CW, RTTY, PSK mode) via the filter
switches (IC3501 and IC3502).
The fi ltered 2nd TX IF signal is amplifi ed by the 2nd TX IF
AMP (Q3504), and applied to the 2nd TX mixer (D3703) via
the attenuator to be converted into the 1st TX IF signal, by
being mixed with the 2nd TX LO signal from the PLL UNIT.
The converted 1st TX IF signal is applied to the 1st TX IF
circuits on the RF UNIT via the attenuator and IF switch
(D3702).
D3703
BPF
CERAMIC
FI3501
IC3401
From the modulation circuits
2nd TX IF->
LPF
IC3501
IC3502
ATT
3rd TX LO signal
(491 kHz)
IC3402
ATT
2nd TX LO signal
(64 MHz)
IF
AM
FILTER
SWITCH
FILTER
SWITCH
P
Q3501
ALC
IF SW
RX circuits
To the 1st TX IF circuits
D506
1st TX IF->
2nd TX MIXER
3rd TX mixer
BPF
CERAMIC
FI3502
IF
AMP
Q3504
4kHz
20kHz
MAIN UNIT
RF UNIT
• 3RD AND 2ND TX IF CIRCUITS
1.6-
HP F
50MHz
8-
7.999999MHz
D1401
LPF
Fc=60 MHz
D201
RX circuits
RF
AMP
D1451
1st TX MIXER
TX SIGNAL->
ATT
RF UNIT
IC1401
1st TX LO signal
(64.485-124.455 MHz)
BPF BOARD
BPFs
(B1–B5)
BPFs
(B5–B9,
B10TX)
IF
AM P
LPF
Q1551
1st TX IF SIGNAL->
From the 2nd
TX IF mixer
To the TX AMPs
ALC
RX circuits
BPF
XTAL
15K
MCF-W
BOARD
FI7001
• 1ST TX IF CIRCUITS
1ST TX IF CIRCUITS (RF UNIT AND MCF-W BOARD)
The 1st TX IF signal from the 2nd TX IF circuits is passed
through the 1st TX IF filter (MCF-W BOARD; FI7001) to
remove unwanted signals in wide bandwidth. The fi ltered 1st
TX IF signal is passed through the TX/RX switch (D1551),
amplifi ed by the IF AMP (Q1551), and applied to the 1st TX
mixer (D1451) via the LPF to be converted into the TX signal
(TX frequency itself), by being mixed with the 1st TX LO
signals from the PLL UNIT.
The converted TX signal is passed through the LPF, and
amplifi ed by the RF AMP (IC1401), then applied to the BPF
circuits via the attenuator.
BPF CIRCUITS
The TX signal from the 1st TX IF circuits is passed through
an LPF or one of BPFs according to the transmitting
frequency, to remove unwanted signals contained in the TX
signal.
Refer to the table on page 4-1 for the filter which the TX
signal is passed through.
The fi ltered TX signal is applied to the TX amplifi er circuits
via the HPF and TX line switch (D201).