AK2500B Datasheet, PDF (9/17 Pages) Asahi Kasei Microsystems – DS3/STS-1 Analog Line Receiver

ASAHI KASEI
[AK2500B]
Digital Loss of Signal(DLOS)
Digital loss detector operates as follows.
- A digital loss detector monitors consecutive 0s and 1s density in recovered data.
- RLOS is set high if 175±5 consecutive 0s is detected.
- RPDATA,RNDATA are set low if ALOS is detected.
- RLOS is set low if 33% 1s density (58 1s in 175 consecutive bits) and no consecutive 100 bits of 0s are
detected.
Normal Operation
RCLK : Recovered from RIN data
RPDATA : Recovered data
RNDATA : Recovered data
RLOS : Low
Peak level of Set Alarm
the incoming
data
< ^Threshold
Level
175 +/- 5 bits of consecutive
0s in the incoming data
DLOS
RCLK : Recovered from RIN data
RPDATA : Recovered data
RNDATA : Recovered data
RLOS : High
ALOS
RCLK : Recovered from EXCLK
RPDATA : Low
RNDATA : Low
RLOS : High
175bits of the incoming data
includes the following data.
1) 58bits of 1s (33% 1s density)
2) No 100bits of consecutive 0s
Peak level of Clear Alarm
the incoming
data
> ^Threshold
Level
Fig. 2 Loss of Signal state diagram
MS0005-E-00
-9-
1999/12