Abstract: A system for converting a high definition video signal corresponding to a high definition picture, into a subsampled video signal compatible with NTSC transmission includes a circuit for performing N-phase subsampling on the high definition video signal to produce N sets of subsamples. Each of the subsamples corresponds to a different geographic position in the high definition picture. The N sets of subsamples are processed during N NTSC video frames, respectively, and the N NTSC video frames form an NTSC picture corresponding to the high definition picture. Each of the N sets of subsamples are processed to map each subsample into a geographic position within the NTSC picture, which corresponds to the geographic position in the high definition picture. By outputting the NTSC samples in a manner which preserves, in the NTSC signal, the relative frame-to-frame geometric offsets used in the sampling process, NTSC flicker on conventional NTSC receivers is minimized.

Abstract: Binary data consisting of command signals and information is converted into a pulse width modulated waveform which is inserted in the non-picture portion of a television video signal and transmitted to remote local subscriber systems to control the television programming provided to local subscribers.

Abstract: In a satellite communications network wherein primary video signals containing address and command data pulses in the vertical blanking intervals are transmitted to a plurality of local television subscriber systems, each local system is provided with decoder/controller/switcher apparatus to extract the data from the signals and effect control of the programming provided to the local subscribers in response to the data.