US Patent 7813445 DTV transmitter and method of processing digital broadcast data therein

A DTV transmitter includes a signal generator, an interleaver, a trellis encoder, and a modulator. The signal generator generates a first data group including first, second and third regions, the first and third regions including main data and RS parity data, the second region including enhanced data coded with a first coding rate, enhanced data coded with a second coding rate, a plurality of known data sequences, signaling information and RS parity data. The interleaver interleaves the first data group to generate a second data group including fourth, fifth and sixth regions, the fifth region including enhanced data, a plurality of known data sequences, signaling information, and RS parity data, the fourth region including main data, RS parity data, and enhanced data. The trellis encoder trellis-encodes the second data group. The modulator modulates a broadcast signal including the trellis encoded second data group.