Abstract: An error detection and correction system in which at least the highest order bit of each data word is given a greater protection against errors in transmission than lower order bits. Useful for digitized TV signals where errors in received high order bits have much worse effect on picture quality than errors in low order bits. A parity is generated for each data word in accordance with a self-orthogonal convolutional code constructed by the use of the base elements of a difference triangle for each bit of the data word, the difference triangles being disjoint, the triangle associated with the highest order bit or bits having a large number or numbers of base elements, and the triangles associated with the lowest order protected bit or bits consisting of a single base element. Errors in received code words are detected and corrected in a decoder including majority logic threshold detectors.

Abstract: A converter to translate a sampled color television video signal, consisting of four pulse-code-modulated 8-bit digital samples during each cycle of the color subcarrier, to a corresponding signal consisting of three pulse-code-modulated 8-bit digital samples during each cycle of the color subcarrier. The four 8-bit samples from present and preceeding cycles are stored in several 8-bit input registers. The 8-bit sample in one of the input registers is coupled to an output register once per cycle. Two predetermined weighted combinations of 8-bit samples in predetermined ones of the input registers are coupled to second and third output registers once per cycle.