XRT75R12D_06 Datasheet, PDF (29/134 Pages) Exar Corporation – TWELVE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH SONET

XRT75R12D
REV. 1.0.1 TWELVE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH SONET DESYNCHRONIZER
FIGURE 9. LOSS OF SIGNAL DEFINITION FOR E3 AS PER ITU-T G.775.
RTIP/
RRing
Actual Occurrence
of LOS Condition
Line Signal
is Restored
10 UI
255 UI
Time Range for
LOS Declaration
10 UI
255 UI
RLOS Output Pin
0 UI
G.775
Compliance
0 UI
Time Range for
LOS Clearance
G.775
Compliance
3.5.4 Interference Tolerance
For E3 mode, ITU-T G.703 Recommendation specifies that the receiver be able to recover error free clock and
data in the presence of a sinusoidal interfering tone signal. For DS3 and STS-1 modes, the same
recommendation is being used. Figure 10 shows the configuration to test the interference margin for DS3/
STS1. Figure 11 shows the set up for E3.
FIGURE 10. INTERFERENCE MARGIN TEST SET UP FOR DS3/STS-1
Sine Wave
N
Generator
DS3 = 22.368 MHz
STS-1 = 25.92 MHz
Pattern Generator ^S
2 ²³ -1 PRBS
Attenuator
∑
Cable Simulator
DUT
XRT75R12D
Test
Equipm ent
FIGURE 11. INTERFERENCE MARGIN TEST SET UP FOR E3.
Sine Wave
Generator
N
17.184mHz
Attenuator 1
Attenuator 2
Signal Source
2²³-1 PRBS S
∑
Cable Simulator
DUT
XRT75R12D
Test
Equipment
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