英文關鍵字
acoustics
black
board
button
depth
detect
determine
device
diagram
digital
display
echo
echosounder
electricity
electronic
emitting
environment
equipment
hydro
instrument
isometric
marine
navigation
operation
physics
pulses
radar
radio
reading
reflected
safety
scheme
science
sea
signal
sonar
sound
sounder
sounding
soundwave
technology
transmitting
type
ultrasonic
underwater
vessel
vibration
water
wave