XRT73R12_07 Datasheet, PDF (74/89 Pages) Exar Corporation – TWELVE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT

XRT73R12
TWELVE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT
TABLE 33: ALARM STATUS REGISTER - CHANNEL N ADDRESS LOCATION = 0XM3
(N = [0:11] & M= 0-5 & 8-D)
REV. 1.0.2
BIT NUMBER
NAME
TYPE
DESCRIPTION
5
Digital LOS Defect R/O Digital LOS Defect Declared:
Declared
This READ-ONLY bit-field indicates whether or not the Digital LOS (Loss of
Signal) detector is declaring the LOS Defect condition.
For DS3 and STS-1 applications, the Digital LOS Detector will declare the
LOS Defect condition whenever it detects an absence of pulses (within the
incoming DS3 or STS-1 data-stream) for 160 consecutive bit-periods.
Further, (again for DS3 and STS-1 applications) the Digital LOS Detector will
clear the LOS Defect condition whenever it determines that the pulse den-
sity (within the incoming DS3 or STS-1 signal) is at least 33%.
0 - Indicates that the Digital LOS Detector is NOT declaring the LOS Defect
Condition.
1 - Indicates that the Digital LOS Detector is currently declaring the LOS
Defect condition.
NOTES:
1. LOS Detection (within each channel of the XRT73R12) is
performed by both an Analog LOS Detector and a Digital LOS
Detector. The LOS state of a given Channel is simply a WIRED-
OR of the LOS Defect Declare states of these two detectors.
2. The current LOS Defect Condition (for the channel) can be
determined by reading out the contents of Bit 1 (Receive LOS
Defect Declared) within this register.
4
Analog LOS Defect R/O Analog LOS Defect Declared:
Declared
This READ-ONLY bit-field indicates whether or not the Analog LOS (Loss of
Signal) detector is declaring the LOS Defect condition.
For DS3 and STS-1 applications, the Analog LOS Detector will declare the
LOS Defect condition whenever it determines that the amplitude of the
pulses (within the incoming DS3/STS-1 line signal) drops below a certain
Analog LOS Defect Declaration threshold level.
Conversely, (again for DS3 and STS-1 applications) the Analog LOS Detec-
tor will clear the LOS Defect condition whenever it determines that the
amplitude of the pulses (within the incoming DS3/STS-1 line signal) has
risen above a certain Analog LOS Defect Clearance threshold level.
It should be noted that, in order to prevent "chattering" within the Analog
LOS Detector output, there is some built-in hysteresis between the Analog
LOS Defect Declaration and the Analog LOS Defect Clearance threshold
levels.
0 - Indicates that the Analog LOS Detector is NOT declaring the LOS Defect
Condition.
1 - Indicates that the Analog LOS Detector is currently declaring the LOS
Defect condition.
NOTES:
1. LOS Detection (within each channel of the XRT73R12) is
performed by both an Analog LOS Detector and a Digital LOS
Detector. The LOS state of a given Channel is simply a WIRED-
OR of the LOS Defect Declare states of these two detectors.
2. The current LOS Defect Condition (for the channel) can be
determined by reading out the contents of Bit 1 (Receive LOS
Defect Declared) within this register.
3
Reserved
71