XRT79L71 Datasheet, PDF (114/441 Pages) Exar Corporation – 1 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC

XRT79L71
REV. P1.0.3
BIT
NUMBER
NAME
4
Analog LOS Defect
Declared
PRELIMINARY
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1 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC
TYPE
R/O
DEFAULT
VALUE
0
DESCRIPTION
Analog LOS Defect Declared:
This READ-ONLY bit-field indicates whether or not the Ana-
log LOS (Loss of Signal) detector is declaring the LOS
Defect condition.
For DS3 application, the Analog LOS Detector will declare
the LOS Defect condition whenever it determines that the
amplitude of the pulses (within the incoming DS3 line sig-
nal) drops below a certain "Analog LOS Defect Declaration"
threshold level.
Conversely, (again for DS3 application) the Analog LOS
Detector will clear the LOS Defect condition whenever it
determines that the amplitude of the pulses (within the
incoming DS3 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
XRT79L71 device) 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.
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.
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