British Broadcasting Corporation

Michael G Croll

John O Drewery

Graham A Thomas

A plasma display device ( ) is provided with circuitry ( ) which modifies at least the R and B color component signals so as to compensate for the displacement of the display elements or sub-pixels for each color component relative to each other in the array. Surprisingly, this increases the ratio of wanted signal to alias spectrum. The modification is effected by an interpolator comprising transversal filters ( R, B). The circuitry can be combined with down-converters ( ) when a high definition source is used. In this case a transversal filter ( G) is also included for the G color component signal.

Color displays

Video signal coding using sub-band coding and phase-segregated coding

An enhanced definition PAL signal (HD-PAL) may be received by a MAC receiver by decoding the signal received with a simple decoder (10), time compressing the luminance and chrominance components of the decoded signal and encoding them in a MAC format (12). The MAC signal is then decoded using an HD-MAC decoder (14) and the signals are expanded by a post processor (16) prior to display.

Method of and apparatus for receiving high definition television signals

Encoded digital television signals having a defined bandwidth are transmitted at reduced bandwidth by regularly omitting (18) one in every n of the signal samples, where n is greater than two and is preferably three or four. At a receiver the omitted samples are regenerated by estimating (26) their values from the samples of the reduced-rate transmitted signal by making use of frequency components outside the normal defined bandwidth of the original signal. The estimation can be achieved by a symmetrical digital transversal filter of which one in every n coefficients is zero, the amplitude/frequency characteristics of the filter being unity throughout the defined bandwidth of the TV signal and antisymmetric about half the mean lower sample rate.

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Horsham, United Kingdom

Michael G Croll