Patent ID: 8437372

Claim:
A digital broadcast transmitter, comprising: a pre-processor configured to pre-process enhanced data, wherein the pre-processor comprises: a frame encoder configured to form an RS (Reed-Solomon) frame, wherein the RS frame includes a plurality of rows including the enhanced data, each of the rows have same size, wherein the frame encoder is further configured to perform a first randomizing processing for the enhanced data, perform an RS encoding for each of columns of a RS frame payload to add parity data for each of the columns, and perform a CRC (cyclic redundancy check) coding to add CRC checksum data for each of rows of the RS frame payload; wherein the enhanced data is included in a data group, the data group including first sequence of predetermined data and second sequence of predetermined data, the first sequence of predetermined data having a first length, the second sequence of predetermined data having a second length, wherein the first length is longer than the second length; a multiplexer configured to multiplex enhanced data packets including the enhanced data with one or more main audio and video, AV, data packets including main AV data; a randomizer configured to perform a second randomizing process for the main AV data in the main AV data packets, wherein the randomizer is further configured not to perform the second randomizing process for the enhanced data in the enhanced data packets; a data interleaving unit configured to interleave data in the enhanced and main AV data packets; a data transmission unit configured to transmit a broadcast signal including the main AV data packet and the enhanced data packets.