| 摘要 |
<p>A robust data extension is added to a standard 8VSB digital television transmission system by encoding high priority data packets in a rate 1/2 trellis encoder, The high priority data 1/2 trellis encoded packets are multiplexed with normal data packets and input into the normal data service of an 8VSB system ( 10). which further contains a rate 2/3 trellis encoder. The combined trellis encoding results in a rate 1 /3 trellis encoding for robust data packets and rate 2/3 trellis encoding form normal packets (1 1 ). Requirements for backward compatibility with existing ATSC compliant systems are met: l)the modulus of the symbol set for robust data transmission being the same as that for an 8VSB signal, 2)maintaining compatibility with existing trellis encoders and decoders, 3 transmitting Reed Solomon parity bytes as normal data, and 4)MPEG compatibility is maintained by guaranteeing that robust data packets will not appear as false MPEG packets</p> |
