The use of studio clean-PAL techniques to feed enhanced distribution systems

Previous work within the BBC resulted in the development of clean PAL coding and decoding methods which allowed almost complete separation of chrominance and luminance signals. These methods have recently been refined to allow absolute separation using non-ideal -realisable-filters, regardless of the number of coding and decoding operations performed. The paper briefly outlines the background to the methods, describes the recent attainment of absolute separability and addresses the possibilities for further development. A flexible hardware test-bed has been developed to allow improved PAL coding and decoding methods to be evaluated under conditions as repeated coding and decoding, recording and transmission