Differences Between Wr1 And Wr2 Boards - Furuno FS-1575 Service Manual

Signal Name
CLK WR DDS / PLL IC clock signal/
DATA WR Frequency data set to DDS / PLL IC/
UNLOCK WR Unlock signal of PLL circuit/
ST DDS WR Data set strobe signal to DDS/
ST PLL WR Data set strobe signal to PLL/
DDS IOUP WR Transfers data to the internal memory of the DDS.
DDS RESET WR Resets the DDS.
5V, 15V Power supply voltage for circuit.
AGC WR AGC control voltage under hardware control.
WR INST Indicates whether or not the WR board is mounted.
36-kHz IF signal. This signal is decoded by the DSP/Main CPU of the
IF WR
T-CPU board.
Displays WR board version information when selecting [MENU] ->
RX HW VER0, 1
9.SERVICE -> 5.TEST -> 1.VERSION.
FIL WR Switches receiving filters.

1. Differences between WR1 and WR2 boards

The WR1 and WR2 boards are different in the 1st IF frequency. This leads to differences in
the1st and 2nd Lo frequencies between the WR boards.
Furthermore, the WR1 board handles Distress and Safety frequencies of 2, 4, 6, 8, 12, and
16MHz, while the WR2 board handles frequencies ranging from 2 MHz to 25 MHz. For this
reason, the RF circuits provide the different width of passband of the filters.
1st Lo
2nd Lo
1st IF
2nd IF
RF FIL 1
RF FIL 2
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.
Table 7.4.2 Differences between WR1 and WR2 Boards
WR1
F + 35.946 MHz
36 MHz
35.946 MHz
36 kHz
7-MHz LPF
18-MHz LPF
7-51
Table 7.4.1 Major Signals of WR Board
Function
WR2
F + 44.946 MHz
45 MHz
44.946 MHz
36 kHz
13-MHz LPF
30-MHz LPF
7.4 WR Board