To be able to transmit television pictures in a digital format on a medium having a limited bandwidth, the picture is subjected to some coding operation and thereby converted into a series of transmission bit blocks TRBn of variable length (for example DCT and variable length coding). Each transmission bit block is divided into a main block Hn comprising at least the most important code words and an auxiliary block Sn comprising the other code words. By carrying out a formatting operation, a group of transmission bit blocks is converted into a channel bit block consisting of a number of sub-channel bit blocks SCBn of equal length. The main blocks are accommodated at the first bit positions of the sub-channel bit blocks and the bits of the auxiliary blocks are spread over the remaining bit positions (Fig. 6E).; It is thereby achieved that the most important information is always found at fixed locations so that the influence of sync losses is reduced considerably.
|Publication status||Published - 30 May 1991|