Table of Contents
Advertisement
SECTION 3.
3-1 RECEIVER CIRCUITS
RF CIRCUITS (MAIN-B UNIT)
The RX signal from the antenna is passed through the TX
power detector (D502, D503), and TX/RX line SW (RL51)
and HPF (L285–L287, L289, C297, C298, C300), and then
applied to the RF AMP (Q281). The amplified RX signal
is passed through the BPF (FI281) to remove unwanted
signals, and then applied to another RF AMP (Q271).
The amplified signal is passed through another BPF
(FI271), and then applied to the 1st IF circuits.
• RF CIRCUITS
To the TX circuits
Q271
FI271
FI281
To the 1st RX
RF
IF circuits
BPF
BPF
AMP
1ST RX IF CIRCUITS (MAIN-B UNIT)
The RX signal from the RF circuits is applied to the 1st IF
mixer (IC241) to be mixed with the 1st RX LO signal from
the DDS circuits, resulting in the 243.95 MHz 1st IF signal.
The 1st IF signal is passed through the LPF (L252, C240,
C269), BPF (FI241) and LPF (L233, C233, C234), and then
applied to the 1st IF AMP (IC242).
The amplified 1st IF signal is applied to the 2nd IF circuits,
through the LPF (L234, C235, C236).
• 1ST RX IF CIRCUITS
IC201
To the 2nd RX
IF circuits
AMP
LPF
LPF
2ND RX IF CIRCUITS (MAIN-B and RF-C UNITs)
The 1st RX IF signal from the 1st IF circuits is applied to
the 2nd RX IF mixer (Q221) to be mixed with the 1st RX LO
signal from the PLL circuits, resulting in the 10.95 MHz 2nd
RX IF signal. The 2nd RX IF signal is applied to the RF-C
UNIT, through J313.
The 2nd RX IF signal is passed through the BPF (FI451)
and LPF (L253, C255, C257), and then amplified by the 2nd
IF AMPs (Q251, Q201 and Q202).
The amplified 2nd RX IF signal is applied to the 3rd RX IF
circuits.
• 2ND RX IF CIRCUITS
RF-C UNIT
Q201
Q251
FI451
Q202
To the 3rd RX
XTAL
IF circuits
AMP
AMP
BPF
10.95 MHz
CIRCUIT DESCRIPTION
D502
D503
PWR
LPF
DET
RL51
Q281
RF
HPF
AMP
1LO
996.1-1076.1 MHz
FI241
From the
BPF
LPF
RF circuits
IC241
1st IF
243.95MHz
MAIN-B UNIT
Q221
From the
1st RX IF circuits
2Lo
233MHz
3RD RX IF CIRCUITS (RF-C UNIT)
The 2nd RX IF signal from the 2nd RX IF circuits is divided
into two paths, and then each signal is passed through the
LPF (L201, C201, C203/L202, C202, C204) and applied to
the 3rd RX IF mixers (the image reduction mixers; D151/
D152) to be mixed with the 3rd RX LO signal (10.914 MHz)
from the MAIN-B UNIT of IC-9100, resulting in the 36 kHz
3rd 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 3rd RX IF signals are independently amplified by the
buffers (Q321/Q371) and IF AMPs (IC301). These amplified
3rd RX IF signals are 90 degrees phase-shifted and
combined by the combiner (IC351), and then applied to the
MAIN-B UNIT of IC-9100, through the MAIN/SUB line SWs
(IC52, IC54 and IC55).
• 3RD RX IF CIRCUITS
MDRIF
IC351
IC351
3rd IF 36kHz
90deg
Main/Sub
SDRIF
line SW
To the MAIN-B UNIT of IC-9100
3 - 1
IC301
Q321
D151
IF
BUFF
AMP
10.914 MHz
From the
1R2R3Lo
2nd RX IF circuits
IC301
Q371
IF
BUFF
AMP
D152
Advertisement
Table of Contents
