This paper describes an example of a modem for 2-resolution digital terrestrial transmission, providing 2 programs in a single 8 MHz channel. For each program, we want to transmit 5 Mbit/s to portable receivers and additionally 5 Mbit/s to fized receivers. In the example, we use OFDM with guard intervals as in Digital Audio Broadcasting. The 2-resolution transmission is achieved by using 2-resolution QAM signal constellation. Reed-Solomon coding gives burst error correction capability to combat the frequency selective nature of the transmission channel. The 2-resolution system can easily be reconfigured into a compatible system, providing highdefinition television to fized receivers.
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