Patent ID: 8208501

Claim:
A digital broadcast transmitter, comprising: a pre-processor pre-processing enhanced data, the pre-processor comprising: an RS frame encoder encoding the enhanced data using a Reed-Solomon scheme; a block-processor encoding the RS-encoded enhanced data at a coding rate of 1/2 or 1/4; a group forming unit forming a data group including the enhanced data and known data, the data group including a first, a second and a third region, the second region being positioned between the first and third regions, the first and third regions including the enhanced data, placeholders for main data and RS parity bytes, and the second region including the enhanced data and placeholders for MPEG header bytes and RS parity bytes, wherein at least one row of the data group comprises of only the known data; a data de-interleaver de-interleaving data in the data group; and a packet formatter forming enhanced data packets including the de-interleaved data by adding header data to the deinterleaved data; a multiplexer multiplexing the enhanced data with one or more main audio and video data; an encoder performing non-systematic RS encoding on the enhanced data packets and adding first parity data to the RS-encoded enhanced data; an interleaver interleaving data in the non-systematic RS encoded enhanced data packets; a trellis encoder having at least one memory and trellis-encoding the interleaved data, the at least one memory being initialized by initialization data when the interleaved data correspond to a beginning of at least one known data sequence; and a data transmission unit inserting synchronization data into the trellis-encoded data, modulating the trellis-encoded data having the synchronization data, and transmitting the modulated data.