XRT73L03 Datasheet, PDF (5/62 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
COMMAND REGISTER CR1-(N) ...................................................................................................... 32
2.4.3 Design Guideline for Setting the Transmit Line Build-Out Circuit ................................................ 32
2.4.4 The Transmit Line Build-Out Circuit and E3 Applications ............................................................. 32
2.5 INTERFACING THE TRANSMIT SECTIONS OF THE XRT73L03 TO THE LINE .......................................................... 32
Figure 16. Recommended Schematic for Interfacing the Transmit Section of the XRT73L03 to the Line ..... 32
TRANSFORMER VENDOR INFORMATION ........................................................................................... 33
3.0 The Receive Section ........................................................................................................................ 33
3.1 INTERFACING THE RECEIVE SECTIONS OF THE XRT73L03 TO THE LINE ............................................................ 33
Figure 17. Recommended Schematic for Transformer-Coupling the Receive Section of the XRT73L03 to the
Line ............................................................................................................................................... 34
Figure 18. Recommended Schematic for Capacitive-Coupling the Receive Section of the XRT73L03 to the Line
....................................................................................................................................................... 34
3.2 THE RECEIVE EQUALIZER BLOCK ..................................................................................................................... 35
Figure 19. The Typical Application for the System Installer ........................................................................... 35
COMMAND REGISTER CR2_(N) ...................................................................................................... 36
3.3 CLOCK RECOVERY PLL ................................................................................................................................... 36
3.3.1 The Training Mode ............................................................................................................................. 36
3.3.2 The Data/Clock Recovery Mode ....................................................................................................... 36
3.4 THE HDB3/B3ZS DECODER ............................................................................................................................ 36
3.4.1 B3ZS Decoding DS3/STS-1 Applications ......................................................................................... 36
Figure 20. An Example of B3ZS Decoding ..................................................................................................... 37
3.4.2 HDB3 Decoding E3 Applications ...................................................................................................... 37
Figure 21. An Example of HDB3 Decoding .................................................................................................... 37
3.4.3 Configuring the HDB3/B3ZS Decoder .............................................................................................. 37
COMMAND REGISTER CR2-(N) ...................................................................................................... 38
3.5 LOS DECLARATION/CLEARANCE ...................................................................................................................... 38
3.5.1 The LOS Declaration/Clearance Criteria for E3 Applications ........................................................ 38
Figure 22. The Signal Levels at which the XRT73L03 declares and clears LOS ........................................... 39
Figure 23. The Behavior the LOS Output Indicator in response to the Loss of Signal and the Restoration of Sig-
nal ................................................................................................................................................. 39
3.5.2 The LOS Declaration/Clearance Criteria for DS3 and STS-1 Applications ................................... 40
TABLE 5: THE ALOS (ANALOG LOS) DECLARATION AND CLEARANCE THRESHOLDS FOR A GIVEN SETTING OF
LOSTHR AND REQEN FOR DS3 AND STS-1 APPLICATIONS .............................................................. 40
COMMAND REGISTER CR0-(N) ...................................................................................................... 40
COMMAND REGISTER CR2-(N) ...................................................................................................... 41
COMMAND REGISTER CR0-(N) ...................................................................................................... 41
COMMAND REGISTER CR2-(N) ...................................................................................................... 41
3.5.3 Muting the Recovered Data while the LOS is being Declared ....................................................... 41
COMMAND REGISTER CR3-(N) ...................................................................................................... 42
3.6 ROUTING THE RECOVERED TIMING AND DATA INFORMATION TO THE RECEIVING TERMINAL EQUIPMENT ............. 42
3.6.1 Routing Dual-Rail Format Data to the Receiving Terminal Equipment ......................................... 42
Figure 24. The typical interface for the Transmission of Data in a Dual-Rail Format from the Receive Section of
the XRT73L03 to the Receiving Terminal Equipment .................................................................. 42
Figure 25. How the XRT73L03 outputs data on the RPOS and RNEG output pins ....................................... 43
Figure 26. The Behavior of the RPOS, RNEG and RxClk signals when RxClk is inverted ............................ 43
COMMAND REGISTER CR3-(N) ...................................................................................................... 44
3.6.2 Routing Single-Rail Format (Binary Data Stream) data to the Receive Terminal Equipment ..... 44
COMMAND REGISTER CR3-(N) ...................................................................................................... 44
Figure 27. The typical interface for Data Transmission in a Single-Rail Format from the Receive Section of the
XRT73L03 to the Receiving Terminal Equipment ........................................................................ 44
Figure 28. The behavior of the RPOS and RxClk output signals while the XRT73L03 is transmitting Single-Rail
data to the Receiving Terminal Equipment .................................................................................. 45
3.7 SHUTTING OFF THE RECEIVE SECTION ............................................................................................................. 45
COMMAND REGISTER CR3-(N) ...................................................................................................... 45
4.0 Diagnostic Features of the XRT73L03 ............................................................................................ 46
4.1 THE ANALOG LOCAL LOOP-BACK MODE .......................................................................................................... 46
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