XR-T7296 Datasheet, PDF (8/16 Pages) Exar Corporation – DS3/STS-1, E3 Integrated Line Transmitter

XR-T7296
DS3 SIGNAL REQUIREMENTS AT THE DSX
For DS3 operation, pulse characteristics are specified at
the DSX-3, which is an interconnection and test point
referred to as the crossconnect. The crossconnect exists
at the point where the transmitted signal reaches the
distribution frame jack. The DSX-3 interconnection
specification tables list the signal requirements (Table 1).
The XR-T7296 can transmit through 450 feet of 782A
cable to the DSX-3 in DS3 mode.
Currently, two isolated pulse template requirements exist:
the ANSI T1.404 pulse template (See Table 3 and Figure
3) and the Bellcore TR-NWT-000499 pulse template. The
pulse transmitted by the XR-T7296 meets these
templates.
Parameter
Line Rate
44.736Mbps $20 ppm
Specification
Line Code
Test Load
Pulse Shape
Power Levels
Bipolar with three-0 substitution (B3ZS)
75 Ω 5%
An isolated pulse must fit the template in Figure 3 or Figure 4.¹ The pulse amplitude may
be scaled by a constant factor to fit the template. The pulse amplitude must be be-
tween 0.36Vpk and 0.85Vpk, measured at the center of the pulse.
For an all 1s transmitted pattern, the power at 22.368 $ 0.002MHz must be -1.8 to
+5.7dBm, and the power at 44.736 $.002MHz must be -21.8dBm to -14.3dBm.^{2, 3}
Notes
1 _{The pulse template proposed by G.703 standards is shown in Figure 4 and specified in Table 4 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 2. DSX–3 Interconnection Specification
Lower Curve
Time
Equation
T  -0.36
-0.36  T +0.36
-0.03
0.5 [1 + sin^π/2 [1 +T/0.18 ]]-0.03
+0.36  T
-0.03
Upper Curve
Time
Equation
T -0.68
-0.68  T  + 0.36
+0.03
0.5[ 1 + sin^π/2 [1 +T/0.34]]+0.03
+0.36
0.05+0.407e^{-1.84(T-0.36)}
Table 3. DSX-3 Pulse Template Boundaries for ANSI T1.404 Standards (See Figure 3. )
Lower Curve
Time
Equation
-0.85  T  -0.36
-0.36  T  +0.36
-0.03
0.5 [1 + sin^π/2 [1 + T/0.18]] -0.03
+0.36  T  +1.4
-0.03
Upper Curve
Time
Equation
-0.85 T -0.68
-0.68  T + 0.36
+0.03
0.5[ 1 + sin^π/2 [1 +T/0.34]] +0.03
-0.68  T 0.36
0.08+0.407e^{-1.84(T-0.36)}
Table 4. DSX-3 Pulse Template Boundaries for Bellcore TR-NWT-000499 Standards (See Figure 4)
Rev. 2.01
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