JRC JFE-380 -, Instruction Manual

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Explanation of Terms
Beam angle: The angle that sound waves spread out from the transducer. Sound waves
spread out in a conical manner taking the center of the bottom surface of the transducer at
the apex of the cone.
Bubbling: The phenomenon where the image of the seabed is interrupted due to air bubbles
caused by the ship's hull or the propeller during a voyage.
IMO: abbreviation for the International Maritime Organization.
MED: abbreviation for the Marine Equipment Directive. This is the directive for marine
equipment in Europe. This directive unifies format approval standards implemented
separately by each European.
NMEA0183: formats for the National Marine Electronics Association. NMEA0183 is the
format used when sending or receiving depth, position, water temperature, ship speed and
other information between marine equipment.
STC: Sensitivity Time Control is used for reduce shallow water clutter. Shallow seabed
echo is strong and deep seabed echo is weak. So, the STC controls the sensitivity to
normalize seabed echo for precision seabed tracking.
Transducer: Device that emits ultrasonic waves in water and receives the signals reflected
off the seabed. This is equivalent to an antenna on a radio.
UTC: abbreviation for the Universal Time Coordinated.
Explanation of Terms viii