Furuno FR-2155 User Manual

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2.33 BEARING SIG GEN Board
The bearing signal generator produces a square wave signal which performs the X-Y coordinate
conversion in the display (processor) unit.
U901 is a U- configured photo interrupter composed of a light emitting diode and a photo tran-
sistor. The light emitting diode and photo transistor are mounted on opposite walls. The timing
disc (photo blanker), which is provided with 60 slits at regular intervals along its circumference,
rotates at a speed of 144 rpm between the two walls.
The photo transistor receives the light emitted by the light emitting diode thru a slit on the tim-
ing disc and converts it into electric current. The output of the photo transistor across R2 repre-
sents a half-rectified sine wave at a frequency of 144 Hz (360 pulses/rotation)
This signal is amplified, reshaped and then sent to the display unit.
5
J901
BEARING SIG GEN Board (MP-3795)
+
-
+12 V
R902
1
U901
R901
HD FL
2
1
S801
RS-1
P902
C
901
C
902
2
3
GND
B.P
P901
12
R
921
C
905
R
903
13
4
14
R904
R905
C
904
+
-
C
903
U902
9
10
+
-
R906
U902
8
5
U902
R
910
R
909
Q902
2SC367
R
908
R
907
Q901
2SA495
R915
R911 to R914
P901
6
7

Furuno FR-2155 Specifications

General

Brand	Furuno
Model	FR-2155
Category	Marine Radar
Language	English