Patent ID: RE42301

Claim:
A method of generating a symbol code composed of symbols manifested as different levels of a plural-level electric signal, said method comprising the steps of: (a) randomizing a stream of data packets, each having a prescribed first number of bytes therein; (b) forward-error-correction coding each of said data packets to generate a respective lateral Reed-Solomon code segment that is included as one of successive segments of a data field included in a succession of data fields, each of said lateral Reed-Solomon code segments consisting of said prescribed first number of bytes plus a prescribed second number of parity bytes; (c) forming groups of said lateral Reed-Solomon code segments containing ones of said data packets that are of at least one prescribed type; (d) forward-error-correction coding bytes in each of transverse paths through each said group of said lateral Reed-Solomon code segments, thereby to generate a respective transverse Reed-Solomon code further including a respective set of transverse Reed-Solomon code parity bytes; (e) assembling each said respective set of transverse Reed-Solomon code parity bytes into a prescribed number of further segments of at least one of said data fields, each of which further segments has a prescribed third number of bytes, said prescribed third number being a sum of said prescribed first number and said prescribed second number; (f) time-division multiplexing, within said data fields, said lateral Reed-Solomon code segments generated in step (b) with said further segments in which said respective sets of transverse Reed-Solomon code parity bytes are assembled in step (e); (g) convolutionally interleaving the successive segments of said data fields to generate successive segments of convolutionally interleaved data fields; (h) trellis coding said successive segments of convolutionally interleaved data fields to generate a trellis code; (i) mapping successive nibbles of said trellis code into respective symbols of said symbol code; and (j) inserting synchronizing signals into said symbol code.