Tx Fil Board - Furuno FS-1575 Service Manual

7.2.6 TX FIL Board

05P0870A: FS-5075
05P0870B: FS-2575
05P0876: FS-1575
The TX FIL board consists of eight Low-pass filters with a different frequency band
between 1605 kHz and 27.5 MHz, a 50-ohm break-in (BK) circuit used to switch the RF
transceiver circuit, a 50-ohm dummy load circuit used to conduct self-tests, and V-SWR
detection circuit for TX FIL board I/O signals.
Basically, the TX FIL board circuits of the FS-1575, FS-2575, and FS-5075 systems are
the same. The differences between the three TX FIL boards are as follows:
1) The TX FIL boards of the FS-5075 and FS-2575 systems are different in the types
of input connector of the TX FIL board. The 05P0870A uses the BNC type
connector, while the 05P0870B used the TMP type connector.
2) The TX FIL boards of between FS-1575 and FS-5075, FS-2575 systems are
different in the power capacity for the FIL circuit.
J1 -> 05P0870A:
BNC CONNECTOR
J2 -> 05P0870B:
TX IN
TMP CONNECTOR
J1
J2
SWR DET
CR1. 2
J4
1 - 3 N.C.
4 CLK TX FIL
5 DATA TX FIL
6 ST TX FIL
7 TX FIL HW VER
8 CHK ON
R65
9 BK ON
0
10 CHK IN VR
11 ALC
12, 13 15V
14 - 16 GND
TX FIL
05P0870A/B
CONFIDENTIAL (internal use only)
This confidential document is used only by FURUNO authorized persons.
It is strictly prohibited to reproduce the document in whole or in part without prior written permission of FURUNO.
L.P.F x8
L1
K5
1.6 - 2.3MHz
K7
2.3 - 3.2MHz
K6
3.2 - 4.5MHz
K8
4.5 - 6.6MHz
K1
6.6 - 9MHz
K2
9 - 14MHz
K3
14 - 20MHz
K4
20 - 27MHz
K1 - K16
U2: Driver
U3: Shift resistor
Fig. 7.2.14 TX FIL Board Block Diagram
7-29
7.2 Transmission Circuit
L18
K9 K17
K18
K10
SWR DET
CR3, 8
K11 R44
51 35W
K12
K13
K14
K15
K16
CR9
CR9
CR10
CR10
3.3V
TX FIL CLK
TX FIL ST
3.3V
AVR
TX FIL DATA
ANT
RX RF
K19
E1
90B
BK ON
CHECK ON
U1 R43
ALC
CHECK IN VR
5V
15V
5V
AVR
W1