Patent ID: 7978697

Claim:
A digital broadcast transmitter, comprising: a pre-processor configured to pre-process enhanced data, the pre-processor further comprising: a block processor configured to selectively perform 1/2 rate coding on enhanced data or 1/4 rate coding on enhanced data, a group formatter configured to insert the coded enhanced data, from the block processor, known data and place holders for main service data into a data group having a plurality of regions, wherein a first region among the plurality of regions has a segment comprised of only the known data and a second region among the plurality of regions has no known data, and a packet formatter configured to remove the place holders for main service data in the data group; a first multiplexer configured to multiplex packets having the enhanced data with packets having the main service data; a trellis encoder configured to trellis-encode the multiplexed data, wherein memories of the trellis encoder are initialized at the start of each sequence of the known data; and a second multiplexer configured to multiplex the trellis-encoded data with field synchronization data and segment synchronization data.