XRT75L06D Datasheet, PDF (84/103 Pages) Exar Corporation – SIX CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH SONET DESYNCHRONIZER

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XRT75L06D
REV. 1.0.4
SIX CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH SONET DESYNCHRONIZER
7.5.5 87-3 Pattern
Figure 59 presents an illustration of the "87-3 Continuous Pattern" Pointer Adjustment Scenario per Telcordia
GR-253-CORE.
FIGURE 59. AN ILLUSTRATION OF THE 87-3 CONTINUOUS POINTER ADJUSTMENT PATTERN
Repeating 87-3 Pattern (see below)
Pointer Adjustment Events
Initialization
Measurement Period
87-3 Pattern
87 Pointer Adjustment Events
No Pointer
Adjustments
NOTE: T ranges from 34ms to 10s (Req)
T
T ranges from 7.5ms to 34ms (Obj)
Telcordia GR-253-CORE defines an "87-3 Continuous" Pointer Adjustment pattern, as a repeating sequence of
90 pointer adjustment events. Within this 90 pointer adjustment event, 87 pointer adjustments are actually
executed. The remaining 3 pointer adjustments are never executed. The spacing between individual pointer
adjustment events (within this scenario) can range from 7.5ms to 10seconds.
Telcordia GR-253-CORE mandates that the Intrinsic Jitter, within the DS3 signal that is de-mapped from a
SONET signal, which is experiencing the "87-3 Continuous" pattern of Pointer Adjustments, must not exceed
1.0UI-pp.
7.5.6 87-3 Add
Figure 60 presents an illustration of the "87-3 Add Pattern" Pointer Adjustment Scenario per Telcordia GR-253-
CORE.
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