XRT73L03 Datasheet, PDF (33/62 Pages) Exar Corporation – 3 CHANNEL E3/DS3/STS-1 LINE INTERFCE UNIT

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PRELIMINARY
3 CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT XRT73L03
REV. P1.0.13
setting the ENDECDIS(n) bit-field in Command
Register (CR2-(n)), to "1".
COMMAND REGISTER CR2-(N)
D4
D3
D2
D1
D0
Reserved
ENDECDIS(n)
ALOSDIS(n)
DLOSDIS(n)
REQEN(n)
x
1
x
x
x
If either of these two methods is used to disable the
HDB3/B3ZS Encoder, the LIU transmits the data as
received via the TPData and TNData input pins.
2.4 THE TRANSMIT PULSE SHAPING CIRCUITRY
The Transmit Pulse Shaper Circuitry consists of a
Transmit Line Build-Out circuit which can be enabled
or disabled by setting the TxLEV(n) input pin or Tx-
LEV(n) bit-field to "High" or "Low". The purpose of
the Transmit Line Build-Out circuit is to permit config-
uration of each channel in the XRT73L03 to transmit
an output pulse which is compliant to either of the fol-
lowing pulse template requirements when measured
at the Digital Cross Connect System. Each of these
Bellcore specifications state that the cable length be-
tween the Transmit Output and the Digital Cross Con-
nect system can range anywhere from 0 to 450 feet.
The Isolated DSX-3 Pulse Template Requirement per
Bellcore GR-499-CORE is illustrated in Figure 14 and
the Isolated STSX-1 Pulse Template Requirement
per Bellcore GR-253-CORE is illustrated in Figure 15.
FIGURE 14. THE BELLCORE GR-499-CORE TRANSMIT OUTPUT PULSE TEMPLATE FOR DS3 APPLICATIONS
D S 3 P u ls e T e m p la te
1.2
1
0.8
0.6
Lower Curve
Upper Curve
0.4
0.2
0
-0.2
-1 _{-0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1}
0 _{0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9}
Tim e, in UI
1 _{1.1 1.2 1.3 1.4}
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