FORWARD ECHO

In a transmission line , an echo propagating in the same direction as the original wave and consisting of energy reflected back by one discontinuity and then forward again by another discontinuity. ( 188 ) Note: Forward echoes can be supported by reflections caused by splices or other discontinuities in the transmission medium ( e.g. , optical fiber , twisted pair, or coaxial tube). In metallic lines, they may be supported by impedance mismatches between the source or load and the characteristic impedance of the transmission medium.