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3 - 1
SECTION 3
CIRCUIT DESCRIPTION
3-1 RECEIVER CIRCUITS
BPF UNIT
The received signals from the “HF ANT1” or “HF ANT2”
connector (0.005−29.999 MHz) are passed through the
attenuators and each BPFs for the frequency coverage. The
fi ltered The received signals are applied to the RF-A UNIT
(Refer to “
RF-A UNIT
”).
ANT UNIT
<The received signals from “HF-ANT1”>
The received signals from the ANT1 connector (30−1150 MHz)
are amplified or attenuated by pre-amplifier/attenuator. The
amplifi ed signals are applied to the RF-B UNIT (Refer to “
RF-B
UNIT
”).
<The received signals from “ANT2”>
The received signals from the ANT2 connector (1150−
3335 MHz) are amplified or attenuated by pre-amplifier/
attenuator. The amplifi ed/attenuated signals are amplifi ed
by one or two RF amplifi ers via band switches, LPFs and
HPFs. The amplifi ed signals are applied to the RF-B UNIT.
(Refer to “
RF-B UNIT
”)
RF-A UNIT
<The received signals from the ANT UNIT>
The received signals from the BPF UNIT are amplifi ed and
fi ltered, then applied to the 1st mixer (IC130), and mixed with
1st LO signals from the PLL UNIT to generate 1st IF signal.
The generated 1st IF signal is fi ltered by one of 1st IF fi lters
( BW=3 kHz, 6 kHz, 15 kHz, 50 kHz or 240 kHz) to remove
unwanted signals. The filtered 1st IF signal is amplified by
1st IF amplifi er, then applied to the 2nd mixer and mixed with
2nd LO signals from the PLL UNIT to generate 2nd IF signal.
The generated 2nd IF signal is amplifi ed by 2nd IF amplifi er,
and passed through the 2nd IF fi lter (BW=50kHz) to remove
unwanted signals. The filtered 2nd IF signal is applied to
the 3rd mixers (D1250 and D1251), and mixed with 3rd LO
signals from the PLL UNIT to generate 3rd IF signal.
The generated 3rd IF signal is amplifi ed by 3rd IF amplifi er
(IC1000), then applied to the MAIN UNIT for demodulation.
<The received signals from the MIX2 UNIT>
The 2nd IF signal from the MIX2 UNIT is filtered by one
of 2nd IF filters (for BW=3 kHz, 6 kHz, 15 kHz, 50 kHz or
240 kHz) to remove unwanted signals. The filtered 2nd IF
signal is amplified by 2nd IF amplifier, then applied to the
3rd mixer, and mixed with 3rd LO signals from the PLL
UNIT to generate 3rd IF signal.
The generated 3rd IF signal is amplifi ed by 3rd IF amplifi er,
and passed through the 3rd IF fi lter (BW=50kHz) to remove
unwanted signals. The filtered 3rd IF signal is applied to
the 4th mixers (D1250 and D1251), and mixed with 4th LO
signals from the PLL UNIT to generate 4th IF signal.
The generated 4th IF signal is amplifi ed by 4th IF amplifi ers,
then applied to the MAIN UNIT for demodulation.
<WFM mode>
In WFM mode, the IF signal from the 3rd IF amplifier is
amplifi ed by two 3rd IF amplifi ers, and fi ltered by two 3rd IF
fi lters (BW=230 kHz), then applied to the IF IC (IC1031) for
FM-demodulation. The demodulated AF signals are applied
to the MAIN UNIT via AF switch (IC1312).
IC130
D600
D1250
D1251
3rd IF signal
to the MAIN UNIT
AF signal
to the MAIN UNIT
MIX1 UNIT
MIX2 UNIT
BPF UNIT
• RX DIAGRAM
ANT UNIT
RF-A UNIT
RF-B UNIT
HF ANT1
0.005–29.999 MHz
HF ANT2
0.005–29.999 MHz
ANT1
30–1150 MHz
ANT2
1150– 3335 MHz
amp.
BPF
amp.
BPF
WFM DEMODULATION
WFM
Det.
amp.
BPF
amp.
BPF
amp.
BPF
IC21
IC301
90°
amp.
BPF
amp.
BPF
amp.
amp.
amp.
amp.
BPF
BPF
BPF
BPF
BPF
BPF
BPF
BPF
BPF
0.005–
29.999 MHz
AF signals
to the MAIN UNIT
3rd IF signal
from the 3rd IF amp.
IC1031
BPF
CERAMIC
IF
AMP
Q1021
IF
AMP
Q1011
BUFF
IC1030
IF
AMP
BPF
CERAMIC
WFM
DET
IC1312
SELECT
SW
BW=230K
BW=230K
• AF DEMODULATOR CIRCUITS (WFM)
RF-B UNIT
<The received signals from “ANT2”>
The received signals from the ANT-2 connector (1150−
3335 MHz) are amplifi ed and fi ltered, then applied to the
1st mixer (MIX1 UNIT; IC301) via band SW (IC1202). (Refer
to “
MIX1 UNIT
”)
<The received signals from “HF-ANT1”>
The received signals from the ANT-1 connector (30−
1150 MHz) are filtered by one of BPFs for the frequency
coverage to remove unwanted signals. The filtered The
received signals are amplified by RF amplifiers, filtered
by band fi lters, then applied to the 1st mixer (MIX1 UNIT;
IC301) via band switch (IC1202). (Refer to “
MIX1 UNIT
”)