Preamble for a digital television system

摘要

The present invention concerns a system for transmitting a plurality of modes of digital television signals within the same transmission channel where one transmission mode is more robust than another mode. The present invention also concerns a system for receiving and decoding such signals. More specifically, an aspect of the present invention involves a method and an apparatus for utilizing a proper length of preamble data for the improvement of reception. Furthermore, another aspect of the present invention involves a method and an apparatus for inserting a preamble into a proper place in a transmitted data stream relative to the filed synchronization data. Another aspect of the present invention involves a method and an apparatus for decoding trellis-coded data, using the predetermined preamble data.

主权项

1. A method, comprising:
receiving a stream of video data packets; and inserting a plurality of preamble packets into said stream of video data packets, wherein said inserting is performed prior to an interleaving of video data contained within a resulting stream of data packets by convolutional interleaving, wherein a length of said plurality of preamble packets in time is selected to correspond to a maximum delay of said convolutional interleaving, wherein a number of said plurality of preamble packets before rate mode coding is 12, and wherein said plurality of preamble packets are encoded with 12/52 rate mode to produce a preamble of two data blocks in length.