Time Variable Gain: Time Variable Gain is a processing step applied to the sonar return to "normalize" the data so that objects of equal size (i.e. fish) appear to be the same size, even if they are separated by a good distance. Time Variable Gain is a fundamental attribute of good sonar, but is often promoted as a feature.

Total Screen Update®: A Humminbird® feature that refreshes and updates all the sonar information on the display when a range change occurs. Without Total Screen Update®, only the most recent sonar information would be drawn to the new range, and the old sonar information would continue to scroll off the screen at the old range.

Transducer: The transducer is part of the sonar system, which mounts on the boat and is in contact with the water, that converts the electrical energy from the transmitter into sound energy, and that forms the sonar beam in turn. Internally, the transducer consists of one or more piezo electric disks that expand by very minute amounts to create the sound wave. This element also works in reverse, converting the returned sound energy back into an electrical signal that the receiver interprets. Transducers are available for many specific mounting applications for the boat, such as a transom mount, trolling motor mount, etc. Humminbird® offers many sophisticated transducers, often with multiple piezo electric elements designed to form specifically-shaped sonar beams, providing the angler with superior tools for finding and catching fish. See Transmitter and SONAR.

Transmitter: The transmitter and receiver are matched parts of the sonar system that send (transmit) and listen to (receive) the sonar signals, and work in conjunction with the transducer. Humminbird® transmitters have an extremely fast cycling design that can send signals up to 60 times per second, as well as produce the varying levels of power output needed for different depths and conditions. Additionally, the transmitter has the capability to create very precise sonar pulses needed for a high degree of target separation. Humminbird® receivers are extremely sensitive, but within a narrow "bandwidth" to discriminate against noise from external sources. Additionally, the receiver offers a wide "dynamic range" which provides the ability to receive very strong signals alternating with very weak signals, without the strong signal overwhelming the weak signal. See Transducer and Noise.

TripLog: TripLog is a Humminbird® feature that provides an on-screen counter for Elapsed Time, Average Speed and Total Distance traveled, and requires a speed input to activate the feature. TripLog appears on the Big Digits View, and can be reset to zero through the TripLog menu.

TrueArch®: TrueArch® is a Humminbird® feature that provides true fish arches, not artificial arches or symbols. Humminbird® units are capable of producing fish arches due to the wide 60° sonar beam of DualBeam PLUS™, an extremely sensitive sonar receiver. See Fish Arch.

Viewing Angle: Viewing Angle is an attribute of an LCD that characterizes visibility of the display when viewing from off the central access, such as when standing to the side of the fishfinder. Wider viewing angles are better because the information remains visible even when viewing from the side.

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