Patent ID: 8391388

Claim:
A transmitter of a digital broadcast signal, the transmitter comprising: an encoder configured to encode enhanced data; a packet formatter configured to generate enhanced data packets including the encoded enhanced data and known data sequences; a multiplexer configured to multiplex the enhanced data packets and main data packets having main data; a data randomizer configured to randomize the main data in the multiplexed data packets; a data interleaver configured to interleave data in the multiplexed data packets; a trellis encoder configured to trellis-encode the interleaved data and to initialize memories included in the trellis encoder by initialization data at a start of at least one of the known data sequences; a backward-compatibility processor configured to generate parity data based on the initialization data and provide the generated parity data to the trellis encoder; and a transmission unit configured to transmit a transmission frame including the trellis encoded data, wherein the transmission frame has a plurality of segments, and wherein the known data sequences are located in specific segments of the transmission frame.