JRC JFS-280, Instruction Manual

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Glossary
Hoisting device: A device to raise and lower the transducer. Also called a hull unit.
Extend: To move the transducer from the storage tank to outside the hull of
the ship.
Storage: To move the transducer from outside the hull of the ship to the
storage tank.
True bearing: Indicates the direction given that true north is set as the top of the
screen.
Heading: Indicates the direction given that the direction of the ship is set as the
top of the screen.
Tilt angle: Function that changes the orientation of the sound waves being
transmitted and received in a vertical orientation from the horizontal.
Speed over ground: Speed of the ship calculated from the speed and the direction in
relation to the seabed.
Speed relative to water: Speed of the ship calculated from the direction of the current at a set
depth, the logs, and the current meter.
Log: Short form of speed log.
TX PRR: Transmission pulse repetition rate.
Clutter: Various noises, from under the sea and the surface of the sea, that
should be removed.
ADC: Acronym for analog to digital converter, which controls the conversion
of analog signals to digital signals.
AGC: Automatic Gain Control. A function that automatically lowers the gain
when the signal is too strong.
RM: Relative Motion. The display for relative motion in which the position
of your own ship is fixed and all targets move in relation to your own
ship.
TVG: Time Varied Gain. A function that uses the gain and the dampening
characteristics of time to restore sound wave signals that have been
damped by time.
STC: Sensitivity Time Control. A function similar to TVG that is used for
short distances.
RCG: Acronym for Reverberation Control of Gain. This process stops the
increase in gain on the TVG curve, if an extremely strong echo is
received, such as interference waves from another ship's sonar,
given that the RGG is on at the time.