| 摘要 |
Digital television signals comprising a plurality of elementary binary streams representing respective TV programs are multiplexed into a single, low-capacity transport stream, which also incorporates packets containing PSI/SI tables, PCR packets and null packets. The transport stream is then modulated and transmitted to a plurality of terrestrial stations for re-broadcasting from terrestrial aerials. Before modulation, packets carrying PSI/SI tables of type PAT, SDT, NIT and EIT are masked by replacing their PIDs with respective, predetermined masking PIDs, null packets are hidden, and the values of the PCR field are saved. The resulting transport stream is remultiplexed with a secondo, conventional transport stream in order to generate a high-capacity transport stream for transmission. On reception, all the packets of the second transport stream are removed, including the associated null packets. The null packets, PSI/SI tables and PCR fields of the first stream are then restored. <IMAGE> |
