Patent ID: 7787559

Claim:
A DTV transmitter for coding data for transmission, the DTV transmitter comprising: a pre-processor for expanding original enhanced data at an expansion rate of N/M by inserting null data, wherein N and M are positive integers and N<M; a data formatter for generating enhanced data packets including the expanded enhanced data and for inserting known data place holders into at least one of the enhanced data packets; a multiplexer for multiplexing the enhanced data packets with main data packets including main data; an RS encoder for RS-coding the multiplexed data packets, the RS encoder adding systematic RS parity data to each main data packet and adding non-systematic RS parity place holders to each enhanced data packet; a data interleaver for interleaving the RS-coded main and enhanced data packets; a known data generator for generating known data symbols; a byte-symbol converter for converting the interleaved data packets into corresponding symbols; and a symbol processor for processing the converted symbols, the symbol processor removing symbols representing the null data, encoding symbols representing the original enhanced data at a rate of N/M, and replacing symbols representing the known data place holders with the known data symbols.