XRT7295AE Datasheet, PDF (7/18 Pages) Exar Corporation – DS3/Sonet STS-1 Integrated Line Receiver

XRT7295AE
DS3 SIGNAL REQUIREMENTS AT THE DSX
Pulse characteristics are specified at the DSX-3, which is
an interconnection and test point referred to as the
cross-connect (see Figure 2.) The cross-connect exists
at the point where the transmitted signal reaches the
distribution frame jack. Table 1 lists the signal
requirements. Currently, two isolated pulse template
requirements exist: the ACCUNET T45 pulse template
(see Table 2 and Figure 4)and the G.703 pulse template
(see Table 3 and Figure 5). Table 2 and Table 3 give the
associated boundary equations for the templates. The
XRT7295AE correctly decodes any transmitted signal
that meets one of these templates at the cross-connect.
Parameter
Line Rate
Line Code
Test Load
Pulse Shape
Specification
44.736 Mbps ¦20 ppm
Bipolar with three-0 substitution (B3ZS)
75 W ¦5%
An isolated pulse must fit the template in NO TAG or Figure 5.¹ The pulse amplitude may be scaled by
a constant factor to fit the template. The pulse amplitude must be between 0.36vpk and 0.85vpk,
measured at the center of the pulse.
Power Levels
For
the
and all 1s transmitted pattern,
power at 44.736 ±0.002MHz
the power at 22.368
must be -21.8dBm
t^±o -01.40.032dMBmH.z^2,m3ust
be
-1.8
to
+5.7dBm,
and
Notes
1 _{The pulse template proposed by G.703 standards is shown in Figure 5 and specified in Table 3. The proposed G.703 standards}
further state that the voltage in a time slot containing a 0 must not exceed ± 5% of the peak pulse amplitude, except for the residue
of preceding pulses.
2 _{The power levels specified by the proposed G.703 standards are identical except that the power is to be measured in 3kHz bands.}
3 _{The all 1s pattern must be a pure all 1s signal, without framing or other control bits.}
Table 1. DSX-3 Interconnection Specification
Lower Curve
Time
Equation
T ± -0.36
0
-0.36 ± T ± +0.28
0.5 (1+sin {p/2}[1+T/0.18])
0.28 ± T
0.11e^-3.42(T-0.3)
Upper Curve
Time
Equation
T±-0.68
0
-0.68 ± T± +0.36
0.5 (1+sin {p/2} [1+T/0.34])
0.36 ± T
0.05 + 0.407e^{-1.84(T-0.36)}
Table 2. DSX-3 Pulse Template Boundaries for ACCUNET T45 Standards (See Figure 4.)
Rev.1.20
7