| 摘要 |
<p>The information to be processed and to be transmitted is formed by information signal blocks (1-12) which are separated from one another by separating signals. The information signal blocks (1-12) are of equal length and are in each case formed by five ''O'' or ''L'' signals. The encoding at the transmitting end is effected by interchanging the information signal blocks (1-12) in their sequence in time. To prevent or at least greatly impede an intrusion into the encoding system, information signal blocks (4, 6, 10) of a given information content are replaced before the transmission. The information signal blocks (4, 6, 10) consisting, for example, only of ''O'' signals (a) are substituted by substitution signal blocks (4', 6', 10') which are generated in a quasi-random signal sequence at the transmitting end. The substitution signal blocks are recognised by comparison at the receiving end and replaced by information signal blocks generated at the receiving end which correspond to the information signal blocks (4, 6, 10) substituted at the transmitting end. <IMAGE></p> |
