3 - 1
SECTION 3
CIRCUIT DESCRIPTION
3-1 RECEIVER CIRCUITS
ANTENNA SWITCHING CIRCUITS (CTRL UNIT)
RX signal from the antenna connector [ANT1] (J1) or [ANT2]
(J2) is passed through the antenna switch (RL501), current
detector (D401), tuner switches (RL351 and RL301), RX line
switches (RL601 and RL621) and LPF, and then applied to
the BPF UNIT.
ATTENUATOR CIRCUITS (BPF UNIT)
The RX signal from the CTRL UNIT is passed through
or bypassed the attenuator circuit (RL141, R141–R143),
depending on the setting.
The RX signal, which is passed though or bypassed the
attenuator circuit (RL141, R141–R143), is applied to the
BPF circuits.
BPF CIRCUITS (BPF UNIT)
The RX signal from the attenuator circuits is passed
through an LPF or one of BPFs, depending on the operating
frequency, to remove unwanted out-of-band signals.
The filtered RX signal is applied to or bypassed the
preamplifi er circuits.
CURRENT
DET
D401
TUNING
NETWORK
LPF
HF ANT1
HF ANT2
BPF
BPF
BPF
BPF
BPF
BPF
RL141
BPF
HPF
BPF
ATTLPF
BPF
PRE
AMP
Q511/Q512
To the 1st RX IF circuits
PRE
AMP
Q532
RL601
RL621
RL301
CTRL UNIT
RL501
RL351
1.6-2.0 MHz
4.0-8.0 MHz
50.0-54.0 MHz
30.0-50.0 MHz
11.0-15.0 MHz
8.0-11.0 MHz
54.0-60.0 MHz
2.0-4.0 MHz
15.0-22.0 MHz
22.0-30.0 MHz
BPF UNIT
0.03-1.6 MHz
NETWORK
UNIT
PREAMPLIFIER CIRCUITS (BPF UNIT)
The RX signal from the BPF circuits is applied to or
bypassed the preamplifi er.
When the Preamplifier function is activated, the RX signal is
amplifi ed by one of preamplifi ers (Q511, Q512 (for 1.8–2.1 MHz)
or Q532 (for 24–50 MHz)).
The amplifi ed or bypassed RX signal is applied to the RF-A
UNIT.
• ANTENNA SWITCHING CIRCUITS TO PREAMPLIFIER CIRCUITS
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