| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical repeater in which erroneous retiming is surely prevented depending on a change point of a reception signal and a count of a counter. SOLUTION: In a digital PLL where a clock signal whose frequency is a 2N multiple of a frequency of a reception signal is counted by a counter to generate a re-timing signal, a change point detection section 31 detects a change point of a received signal, and a phase discrimination section 32 discriminates the change point of the received signal based on criteria by counts '1-14', '16-29', '15', and '30 or 31' of a counter 33. In the case that the reception signal is changed by the count '30 or 31', the counter 33 presets the count to '16' and provides an output of a normal re-timing signal of the received signal to a re-timing section 35. |
