Technical information

EQ-55 Operators Manual 950-7001001/Iss 1.2
Appendix B Glossary Page B.7
Kongsberg Simrad Mesotech Ltd.
Port Coquitlam, BC - Canada
TRANSDUCER
The transducers serve as the acoustic "loudspeaker" and "microphone" to send and
receive the signals through the water. Transducers are most often made from
ceramic elements carefully built into a robust housing. The ceramic elements
change shape when a voltage is placed across them (when the EQ 55 transmits a
signal), and they also generate a voltage when they encounter sound waves (as
when the EQ 55 is receiving an echo).
TVG
Time Varied Gain. This is a method used to compensate for the weakening of an
echo as the distance it travels increases. It involves gradually increasing the
sensitivity of the receiver circuits, so as to adjust for increased range of
targets whose echoes are arriving.
UNITS
"Units" refers to the measurement unit used in the range display. The user may
select the displayed units to be one of the following; meters, feet, fathoms or passi
braza.
VRM
Variable Range Marker. This refers to a horizontal white line shown on the
display screen. There are separate Variable Range Markers for low frequency and
high frequency channels. The user can measure the range to targets shown on the
display screen by use of these VRMs. The depth to the VRM can be seen in the
small display window in the lower left corner of the display window.
WHITE LINE
White Line is a control which places a light colored line slightly below the
displayed sea floor. The purpose of this is to help the user detect targets, such as
fish, which are very close to the sea floor and whose echoes tend to
merge with those of the sea floor itself.
ZOOM
See EXP.