Television stations are getting ready to zap ghosts. The shadows are produced when a TV receiver picks up an echo that arrives an instant after the main signal. To wipe out ghosts, broadcasters and cable operators can send a reference signal in the intervals between picture frames. A chip in the TV or a set-top box will detect ghosts in the reference signal and thus pinpoint and zap ghosts in the picture itself.
Ghost-busting should be good business for Philips Electronics, whose reference signal was picked as the U.S. standard. About a third of U.S. broadcasters have spent from $300 to $4,000 apiece for gear to transmit reference signals. Field tests are expected later this year in Europe, Brazil, and Australia. Japan and South Korea already use older, analog reference signals. Set-top ghost cancelers that work off the signals will go on sale from Philips next year at less than $200.