| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a signal interruption detection circuit capable of equalizing a bit error rate at the time of signal interruption detection regardless of a bit rate even in the case where signals of different bit rates are received in time division manner. <P>SOLUTION: A signal interruption detection circuit 1 includes signal detection parts (20 and 60) which use light reception level threshold values (201 and 601) specific to a plurality of bit rates to detect the presence in a signal of each bit rate that is contained in an output signal 102 of a signal input part 10, a bit rate determination part 70 which determines to which of the plurality of bit rates the output signal 102 of the signal input part 10 belongs, and a signal interruption alarm generating part 80 which outputs a signal (an LOS signal 804 of low level voltage) representing signal interruption in the case where absence of the signal is detected by the signal detection parts (20 and 60) for the bit rate determined by the bit rate determination part 70. <P>COPYRIGHT: (C)2012,JPO&INPIT |
