Patent ID: 6480239
Filing Date: 2002-11-12
Classification: H04N

Abstract:
An apparatus for transmitting a television signal divided into a plurality of successive fields for reception by a television receiver including adaptive ghost suppression filtering, each said field consisting of a prescribed number of lines of information, said lines being of uniform respective duration, said apparatus characterized by including:a reference signal generator for transmitting during a prescribed single line of each of said fields a first ghost-cancellation reference signal and a second ghost-cancellation reference signal different than said first ghost-cancellation reference signal, each of said first and said second ghost-cancellation reference signals being transmitted with a modulation swing less than the maximum modulation swing available but more than half said maximum modulation swing, the relative phases of said first and said second ghost-cancellation reference signals varying from field to field in prescribed pattern to facilitate their separation at said television receiver, said first ghost-cancellation reference signal having a prescribed first duration longer than half a line duration to provide said television receiver sufficient energy for detecting ghosts with long differential delay and low energy to furnish a basis for calculation of adjustments of said adaptive ghost suppression filtering to suppress said ghosts with long differential delay and low energy, and said second ghost-cancellation reference signal having a prescribed second duration shorter than half a line duration to facilitate more rapid calculation of adjustments of said adaptive ghost suppression filtering in said television receiver to suppress ghosts with substantial energy and less differential delay.