| 摘要 |
PURPOSE:To simplify the circuit constitution, by using the bipolar signal in which one bit mark is present every N(integer 2 or more) bits, as the monitor signal for spare line. CONSTITUTION:The bipolar monitor signal of n-series is inputted to the rectifying cicuit 101 and converted into RZ signal 2. By feeding one series of RZ signal 2 to the sampling pulse pick up circuit 102', the sampling pulse 3' having 1/N frequency is produced. On the other hand, RZ signal 2 is converted into modified monitor signal 301 being NRZ signal at the 1/2 frequency dividing circuit 201. The phase comparison circuit 202 performs the value of the signal 301 at the production of the pulse 3' with the value immediately before, and if in opposite phase, no code error pulse is outputted to the output 6', and if in-phase, code error pulse is outputted to the output 6'. |
