A form of interference caused by signal reflections.

Signals that are reflected more take a longer path to reach the receiver than those that are reflected less. The receiver will synchronize to the strongest signal, with the weaker signals traveling via different paths causing ghostly images superimposed on the main image. Since many ATV schemes offer increased horizontal resolution, ghosts can have a more deleterious effect on them than on ordinary NTSC signals. There have been many demonstrations of ghost canceling/eliminating systems and robust transmission systems over the years. It is probable that these will have to be used for HDTV.