Spatially adaptive sub-branches for HD-MAC

The authors describe how spatially adaptive filtering can be used in the HD-MAC system to increase the apparent resolution and to indicate how it can be used in conjunction with motion compensation. Simulated systems of five and seven branch HD-MAC transmission systems are constructed, giving results that have a substantial improvement in resolution over a three branch system without introducing objectionable switching artefacts or requiring a major increase in high definition receiver complexity. The MAC channel provides sufficient capacity for the DATV requirements of either of these systems. The quality of the picture decoded by a conventional MAC receiver is adequate and not worse than that received using the basic HD-MAC system. A further system which uses motion compensation in regions of coherent motion and adaptive filtering where motion compensation fails is being developed