| 摘要 |
<p>A digital transmission system comprising a transmitter (3, 5, 7, 8) and a receiver (14, 15, 16, 18). The medium (6) comprises an information channel (T1, T2, ..., Tn) and an auxiliary channel (Tn+1). Through the information channel information is transmitted, for example a digital audio signal. Through the auxiliary channel an auxiliary signal is transmitted. This auxiliary signal comprises sync information (100, 101, 102, 103, 104, 105) and additional information (106). The auxiliary signal is composed of successive blocks (..., Bn-1, Bn, Bn+1, ...). A first block (Bn) comprises a first block section (header) and a second block section (body). The first block section of the block (Bn) contains a sync word (101) and a first codeword (102), in this order. The first block section of the second directly successive block (Bn+1) contains a sync word (104) and a second codeword (105), in this order. The first codeword (102) expresses that the second block section (106) of the first block (Bn) contains additional information. If there is also additional information in the second block section (107) of the second block, the two codewords are equal. If the block section (107) does not contain additional information, the two codewords are unequal. The first block section of the first block (Bn) further contains a third codeword (100), the sync word (101) and the first codeword (102), in this order. The first block section of the second block (Bn+1) further contains a fourth codeword (103), a sync word (104) and a second codeword (105), in this order. The fourth codeword also expresses that additional information is contained in the second block section (106) of the first block (Bn). The third codeword is now equal to the fourth codeword if the second block section of the block (Bn-1) directly preceding the first block (Bn) also contains additional information. The two codewords are unequal if the second block section of this block (Bn-1) does not contain additional information. <IMAGE></p> |
