Digital broadcast transmitter/receiver having improved receiving performance and signal processing method thereof

A signal processing method of a digital broadcast transmitter comprising:

• randomizing, by a randomizer, a transport stream which includes at least one robust data packet;
• inserting, by a known data inserting unit, specified known data recognizable by a receiver;
• first Reed-Solomon (RS) encoding, by a first RS encoder, data resulting from the inserting the known data;
• performing interleaving, by an interleaver, of a robust data packet included in the first RS encoded data and reformatting the interleaved robust data packet;
• performing a trellis encoding, by a trellis encoder, of the interleaved data to produce trellis encoded data using parity data;
• changing, by a second RS encoder, a parity of the parity data used in the trellis encoding by performing a second RS encoding of the robust data packet included in the trellis-encoded data, and using the changed parity in the parity data used in the trellis encoding;
• and
• modulating, by a modulator, the trellis encoded data and performing a Radio Frequency (RF) up-conversion of the modulated data.