Patent ID: 7826498

Claim:
A digital broadcast transmitter, comprising: a pre-processor configured to pre-process mobile service data, wherein the pre-processor comprises: a group formatter configured to de-interleave a first data group to output a second data group and to provide the de-interleaved data to a packet formatter, the first data group including a plurality of segments, a number of mobile service data in an Nth segment of the first data group being less than a number of the mobile service data in an (N+I)th segment of the first data group, the number of mobile service data in the (N+1)th segment of the first data group being less than a number of mobile service data in an (N+2)th segment of the first data group, each packet in the second data group having a length of 207 bytes, wherein signaling information on a transmission parameter is used in each of the data groups, and the signaling information on the transmission parameter includes a Reed-Solomon (RS) code mode field indicating an RS code mode for an RS frame, and the packet formatter configured to remove place holders for main service data in the second data group; a first multiplexer configured to multiplex the mobile service data with the main service data; a trellis encoder configured to trellis-encode the multiplexed data; and a second multiplexer configured to multiplex the trellis- encoded data with field synchronization data and segment synchronization data; wherein the digital broadcast transmitter performs (223, 187)-RS encoding on the RS frame and generates 36 parity bytes when the RS code mode field indicates a first RS code mode, and the digital broadcast transmitter performs (235, 187)-RS encoding on the RS frame and generates 48 parity bytes when the RS code mode field indicates a second RS code mode.