| 摘要 |
In this method, which can be used, in particular, in transmission systems and in magnetic storage and recovery systems for digital data, for example three bits in each case (three time intervals T) of a binary data signal are combined to form one word. This word corresponds to data cells of the transmission or recording signal. A data cell (Z) exhibits six possible points of signal change (P1 to P6). The binary data signal is converted into a transmission or recording signal in such a manner that a minimum distance (3/2 T) and a maximum distance (6 T) is always ensured so that self-clocking is possible during the reading. Since it is not sufficient only to pay attention to the signal changes within one data cell (Z) but care must also be taken that two signal changes (P5 and P1) of adjacent data cells (e.g. Z4 and Z5) are not closer together than the required minimum distance (3/2 T), the present word is in each case compared with the preceding and following word. If it is found for a word, that a signal change should take place at a point (P5) which is not the minimum distance (3/2 T) away from the point at which a signal change (P1) for another word should take place, the two signal changes are combined at one point (P6). For this purpose, the device for carrying out the method has a coding device with three coders (17, 24, 29) for the present, preceding and following word and switching means (33) which provide a signal change at the boundary (P6) between the data cells (Z4, Z5) instead of the two prevented signal changes (P1, P5). <IMAGE> |
