Patent ID: 7940855

Claim:
A digital broadcast transmitter, comprising: a pre-processor configured to pre-process mobile service data, wherein the pre-processor comprises: a first interleaver configured to interleave symbols corresponding to the mobile service data according to the following equation: P ( i )={ S×i ×( i+ 1)/2} mod L, wherein 0≦i≦L−1, L≦K, L=2 n , n and S are integers, and K is a number of symbols being inputted to the first interleaver, a group formatter configured to map data corresponding to the interleaved symbols into at least one region of a data group and add place holders for main service data and non-systematic RS parity data to the data group, and a packet formatter configured to remove the place holders for the main service data and the non-systematic RS parity data after deinterleaving the data group in a data deinterleaver, and to generate mobile service data packets having data in the data group in which the place holders for the main service data and the non-systematic RS parity data are removed, wherein the packet formatter is the last process in the pre-processor; a first multiplexer configured to multiplex the mobile service data packets with main service data packets having the main service data; a post-processor configured to post-process data in the multiplexed data packets; and a second multiplexer configured to multiplex the post-processed data with field synchronization data and segment synchronization data.