FREMGANGSMAADE OG SYSTEM TIL TRANSMISSION OG MODTAGELSE AF SIGNALER TIL HOEJOPLOESNINGS-TV

摘要

A hybrid television signal of less transmission power or better signal to noise performance is made up by removing low frequency analog components from the video signal, digitizing them and sending them as data in non-active video portions of the transmitted signal. A two step hybridization process, with the first step removing the line averaged value of the video components of the video signal and the second step removing the remainder of the video components under 200 KHz, is described. Temporal filtering, signal pre-emphasis, compression, dispersal and double sideband suppressed carrier modulation about a centered carrier are disclosed for reducing peak signal amplitudes and for minimizing co-channel interference to and from NTSC signals. In an FM implementation, the benefits of the hybrid signal are realized as a reduction in bandwidth and consequent improved noise performance. The hybrid signal system is uniquely adapted to a high definition television signal in a limited frequency channel.