Patent ID: 8351428

Claim:
A digital broadcast transmitter, comprising: a pre-processor for pre-processing enhanced data, wherein the enhanced data and known data are included in a data group, wherein at least three of plurality of sequences of the known data are spaced regularly in the data group, wherein at least one row of the data group is comprised of only the known data immediately after a row of the data group comprising of the known data and the enhanced data, and wherein the pre-processor further comprising: a randomizer for randomizing the enhanced data; a first encoder for generating data frames including the randomized data; a second encoder for encoding the enhanced data included in the data encoded by the first encoder with a coding rate of G/H which is less than 1; a group formatter for forming the data group having a plurality of regions with the data encoded by the second encoder and the known data; a data de-interleaver for de-interleaving the data included in the data group; and a packet formatter for adding header data to the de-interleaved data to generate data packets; a multiplexer for multiplexing the enhanced data with one or more main audio and video (AV) data; a trellis encoder for having at least one memory and trellis-encoding the multiplexed data, the at least one memory being initialized when data corresponds to a start of the sequences of the known data; and a data transmission unit for inserting synchronization data into the trellis-encoded data, modulating the trellis-encoded data having the synchronization data, and transmitting the modulated data.