| 摘要 |
For the transmission of data by way of a fiber-optical path, three-bit code words representing eight different signal levels are generated in respective signal periods 2T and are converted into pairs of ternary luminous waveforms of duration T having two possible amplitude levels L (low) and H (high). Each waveform pair includes at least one but not more than two light pulses H, of a width not exceeding T/2, occurring in either of two time positions within a cycle T. At the receiving end, the incoming light pulses are modulated-either before or after conversion into electrical signals-with a ramp signal of recurrence period T which transposes the pulses H to either of two elevated amplitude levels depending upon their time position within a cycle, with the pulses L remaining at a low level. The resulting electrical pulses are integrated over successive periods equal to T and sampled in each of these periods for comparison with predetermined thresholds. |
