| 摘要 |
<p>PURPOSE: To realize an encoding method with multilevel error protection according to the importance of data. CONSTITUTION: A digital signal (e.g. digitized television signal) follows a source encoding step and a channel mapping step. The source encoding step represents the television signal 101 with data streams and the channel mapping step, on the other hand, is like a difference in the probability that data elements of the data streams are misdetected by a receiver. The 1st data streams b1 to b3 carry components of the most important television signal and are so mapped that the data elements have minimum error probability. The 2nd data streams carry components b4 and b5 , etc., of all television signals which are not more important than the 1st data streams b1 to b3 and are so mapped that the data elements have larger error probability than the 1st data streams b1 to b3 . In general, similar actualization is possible with an arbitrary number of data streams.</p> |
