| 摘要 |
PURPOSE:To prevent an optical output from being continuously outputted due to an abnormality of a terminal equipment in the passive double star system optical burst signal transmission. CONSTITUTION:An LD drive section 1 generates an LD drive signal S2 in response to a burst signal S1. An LD 2 generates an optical signal output in response to the LD drive signal S2. A PD 3 monitors an optical signal output S3 to generate a monitor signal S4. An optical output interrupt detection section 4 outputs an optical output interrupt signal S5 based on the monitor signal S4. A burst detection section 510 confirming the burst signal S1 generates a burst signal detection pulse S6. A comparator section generates an optical output alarm pulse S7 in the case of 'absence of the burst signal but presence of an optical output' representing an alarm state based on the burst signal detection pulse S6 and the optical output interrupt signal S5. Upon the detection of the alarm state once, a latch section 7 generates a control signal S8 used to latch an optical output stop state thereby stopping the optical output. |
