Patent ID: 7869357

Claim:
A digital broadcast transmitter, the digital broadcast transmitter comprising: a randomizer configured to randomize enhanced data; a first encoder configured to generate data frames including the randomized enhanced data by performing at least one of error correction encoding and error detection encoding on the randomized enhanced data; a second encoder configured to encode the enhanced data in the data frames with a coding rate of G/H, wherein G and H are positive integers and G is less than H; a group formatting unit configured to map a portion of the enhanced data encoded by the second encoder into a first data group and to add a plurality of known data sequences, MPEG header data holders, main audio and video (AV) data holders, and parity data holders to the first data group; a deinterleaver configured to deinterleave data included in the first data group and to output a second data group; a packet formatter configured to remove the main AV data holders and the parity data holders in the second data group and to replace the MPEG header data holders in the second data group with MPEG header data, thereby outputting K numbers of enhanced data packets per the second data group, wherein the MPEG header data are positioned at a starting position of each enhanced data packet, and wherein K is an integer greater than 1; a multiplexer configured to multiplex the enhanced data packets with main data packets including AV data; an interleaves configured to interleave data in the multiplexed enhanced and main data packets and to output a third data group, wherein the third data group comprises the portion of the enhanced data, the plurality of known data sequences, the MPEG header data, and the main A/V data; a trellis encoder configured to have at least one memory and to trellis-encode data in the third data group, the at least one memory being initialized at a beginning of each known data sequence; and a data transmission unit configured to multiplex segment synchronization data and field synchronization data with the trellis-encoded data, to modulate the trellis-encoded data multiplexed with the segment synchronization data and the field synchronization data, and to transmit a broadcast signal including the modulated data.