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VHF ANT
UHF ANT
LPF
LPF
TX/RX
SW
L407CD
TX/RX
SW
RL751
To the VHF TX Circuits
UHF TX Circuits
SWR
DET
D801/D811
SWR
DET
D501/D511
LPF
PA-B UNIT
BPF
PRE
AMP
Q1251
D1352-D1354,
D1351
ATT
BPF
BPF
BPF
ATT
VRX
HPF
HPF
HPF
RF
AMP
IC2251
D2351-D2354
RF-B UNIT
To the VHF 1st RX IF circuits
To the UHF 1st RX IF circuits
URX
VHF RF CIRCUITS (RF-B UNIT)
VHF band RX signal from the antenna connector [144MHz
ANT] (CHASSIS; J1) is passed through the SWR detecter
(PA-B; D801, D811), LPF (PA-B; L771–L773, C771–C777),
TX/RX SW (PA-B; RL751) and LPF (PA-B; L763, C770), and
then applied to the RF-B UNIT.
The RX signal from the PA-B UNIT is passed through the
HPF (L1353, L1354, C1355–C1357), and then passed
through or bypassed the attenuator circuit (D1351–D1354,
R1352–R1354), depending on the setting.
The RX signal, which is passed though or bypassed the
attenuator circuit (D1351–D1354, R1352–R1354), is passed
through the BPF (D1301, D1302, L1301, L1302, C1301,
C1302), and then applied to the RF AMP (Q1251).
The amplified RX signal is passed through the two-
staged BPF (D1209–D1211, L1202, C1203, C1206,
and D1202–D1204, L1201, C1201, C1205) and HPF
(L1111–L1114, C1111–C1114, C1116–C1117, C1119), and
then applied to the 1st RX IF circuits.
UHF RF CIRCUITS (RF-B UNIT)
UHF band RX signal from the antenna connector [430MHz
ANT] (CHASSIS; J2) is passed through the SWR detecter
(PA-B; D501, D511), LPF (L451, L452, C451–C455), TX/
RX SW (PA-B; D471–D473) and LPF (L471, C471, C472,
C475), and then applied to the RF-B UNIT.
The RX signal from the PA-B UNIT is passed through the HPF
(L2361, L2362, C2361–C2363, C2359), and then passed
through or bypassed the attenuator circuit (D2351–D2354,
R2352, R2354, R2355), depending on the setting.
The RX signal, which is passed though or bypassed the
attenuator circuit (D2351–D2354, R2352, R2354, R2355),
is passed through the BPF (D2301, D2302, L2301, C2301,
C2302), and then applied to the RF AMP (Q2251).
The amplified RX signal is passed through the two-
staged BPF (D2201–D2203, L2204, C2202, C2204, and
D2204–D2206, L2205, C2205, C2206) and HPF (L2210,
C2210), and then applied to the 1st RX IF circuits.
IF
AMP
IC1221
BUFF
Q1251
IF
AMP
IC1221
Σ
IC1222
To the demodulator circuits
IF
AMP
Q1051
BUFF
Q1201
D1101
IF
AMP
Q1071/Q1072
D1102
90deg
IC1222
Q721/Q722/
Q723/Q724
IF
AMP
Q741
BPF
XTAL
64.455MHz(BW=3kHz)
BPF
XTAL
64.455MHz(BW=15kHz)
FI911
ATT
BPF
XTAL
64.455MHz(BW=6kHz)
FL-430(Optional)
FL-431(Optional)
LPF
fc=60MHz
LO
AMP
Q811
LPF
BUFF
IC1121
BUFF
IC1121
LO
AMP
Q1141
2nd RX LO
1st RX/TX LO
BUFF
IC1121
From the preamplifier circuits
90deg
ATT
LPF
LPF
RF-A UNIT
64.485~
124.455 MHz
from PLL UNIT
from PLL UNIT
HF 1ST RX IF CIRCUITS (RF-A UNIT)
The RX signal from the BPF UNIT is passed through the
LPF, which removes unwanted signals (60 MHz and higher),
and then applied to the 1st RX IF mixer (Q721–Q724) to be
mixed with the 1st RX LO signal (64.485–124.455 MHz) from
the PLL UNIT, resulting in the 64.455 MHz 1st RX IF signal.
The 1st RX IF signal is amplified by the 1st RX IF AMP
(Q741) and passed through one of the 1st IF fi lters (FI911;
FL-434, or optional FL-430 or FL-431), which has different
passband widths, according to the IF fi lter setting.
The fi ltered 1st RX IF signal is amplifi ed by the RX IF AMPs
(Q1051 and Q1071, Q1072), and then applied to the 2nd RX
IF circuits.
HF 2ND RX IF CIRCUITS (RF-A UNIT)
The 1st RX IF signal from the 1st RX IF circuits is divided
into two paths, and then each signal is applied to the 2nd RX
IF mixers (the image reduction mixers; D1102/D1101) to be
mixed with the 2nd RX LO signal (64.491 MHz) from the PLL
UNIT, resulting in the 36 kHz 2nd RX IF signal.
The image reduction mixer removes image frequency
components by using two LO signals which are 90 degrees
phase-shifted from each other.
The 2nd RX IF signals are independently amplified by the
buffers (Q1201/Q1251) and IF AMPs (IC1221).
These amplifi ed 2nd RX IF signals are 90 degrees phase-
shifted and combined by the combiner (IC1222), and then
applied to the MAIN UNIT.
• VHF/UHF RF CIRCUITS
• HF 1ST RX IF AND 2ND RX IF CIRCUITS