| 摘要 |
Orthogonal-diphase coded digital signals are transferred in bursts on a transmission line. In order to facilitate synchronization of the signal receiver to the incoming signal bursts an extra pulse is added at the beginning of each transmitted burst, the polarity of this pulse being opposite to that of the following signal element. At the receiver this extra pulse is detected by comparison of the received signals with a threshold voltage and the next zero transition is then used as a basis for the synchronization. The threshold voltage will be self-adaptive if it is allowed to decrease exponentially with time from a start value corresponding to a short transmission line to a final value corresponding to a long transmission line. Furthermore, in order to eliminate DC residuals an extra pulse may be added at the end of each transmitted burst, the polarity of this pulse being opposite to that of the preceding signal element. |
