Hd Signal - Furuno FAR-2107 Series Service Manual

2. HD signal

HD signals are detected by turning on and off the lead switch by the magnet mounted on
the drive gear. This output pulse length varies with the antenna rotation. The period in
which the heading pulse is turned on is in a range of 0 to 90 degrees. The duty ratio is
1:4. See page.4-77 for related information.
Driven gear
HD detection lead SW
Fig. 7.2.11 Installation of B.P GEN in Antenna unit of
Fig. 7.2.12 Block Diagram and Layout of B.P GEN board
Drive gear
B.P GEN board
J901
1. HD
2. GND
3. BP
4. N.C
5. +12V
R4 R7
C4
R3
U3
R40
[J902-2]
Heading SW
(Reed SW)
magnet
Antenna Motor
7-17
Magnet for HD detection lead SW
X-band Radar
Q3
U1
R13
Q4
[J902-1]
7.2 Antenna Unit
+12V
BP
HD