To call to mind:; SYN. recall.
Repetition of a sound wave, or of a radar or sonar signal, by reflection from a surface. By accurately measuring the time taken for an echo to return to the transmitter, and by knowing the speed of a radar signal (the speed of light) or a sonar signal (the speed of sound in water), it is possible to calculate the range of the object causing the echo (echolocation).
A similar technique is used in echo sounders to estimate the depth of water under a ship's keel or the depth of a school of fish. + prikaži više