A wave that has been reflected by a discontinuity in the propagation medium. A wave that has been reflected or otherwise returned with sufficient magnitude and delay to be perceived.
echo attenuation - In a communication circuit (4- or 2-wire) in which the two directions of transmission can be separated from each other, the attenuation of echo signals that return to the input of the circuit under consideration.
echo cancellation - In a system, the reduction of the power level of an echo or the elimination of an echo.
echo check - A check to determine the integrity of transmission of data, whereby the received data are returned to the source for comparison with the originally transmitted data.
echo command - A programming language command that causes an echo response from a computer to be displayed on a monitor or printer for analysis or monitoring of the progress of processing.
echo line - In computer systems, on a hard-output or display device, a line of information that verifies (reflects) data entered into the computer.
echoplex - An echo check used in public switched networks operating in the full-duplex transmission mode, i.e., the two-way-simultaneous mode.
echo sounding - The measurement of the depth of a body of water or the distance to an object in a body of water by measuring the time it takes sound or electromagnetic waves of known velocity to reflect from the bottom of the water body or from the distant object.
echo suppressor - A device for connection to a two-way telephone circuit to attenuate echo signals in one direction caused by signals in the other direction.