XRT73L03 Datasheet, PDF (42/62 Pages) Exar Corporation – 3 CHANNEL E3/DS3/STS-1 LINE INTERFCE UNIT

XRT73L03 3 CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT
REV. P1.0.13
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PRELIMINARY
FIGURE 22. THE SIGNAL LEVELS AT WHICH THE XRT73L03 DECLARES AND CLEARS LOS
0 dB
-12 dB
-15dB
LOS Signal Must be Cleared
Maximum Cable Loss for E3
-35dB
LOS Signal may be Cleared or Declared
LOS Signal Must be Declared
Timing Requirements associated with Declaring
and Clearing the LOS Indicator
The XRT73L03 was designed to meet the ITU-T
G.775 specification timing requirements for declaring
and clearing the LOS indicator. In particular, a chan-
nel of the XRT73L03 declares an LOS between 10
and 255 UI (or E3 bit-periods) after the actual time
the LOS condition occurred. The channel clears the
LOS indicator within 10 to 255 UI after restoration of
the incoming line signal. Figure 23 illustrates the
LOS Declaration and Clearance behavior in response
to the Loss of Signal event and then the restoration of
the signal.
FIGURE 23. THE BEHAVIOR THE LOS OUTPUT INDICATOR IN RESPONSE TO THE LOSS OF SIGNAL AND THE RESTO-
RATION OF SIGNAL
Actual Occurrence
of LOS Condition
Line Signal
is Restored
RxIN
10 UI
255 UI
Time Range for
LOS Declaration
10 UI
255 UI
RLOS Output Pin
0 UI
G.775
0 UI
Time Range for
LOS Clearance
G.775
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