
XRT73L00
E3/DS3/STS-1 LINE INTERFACE UNIT
REV. 1.2.0
á
II
2.4.3 Design Guideline for Setting the Transmit Line Build-Out Circuit ..................................... 26
C
OMMAND
R
EGISTER
CR1 (A
DDRESS
= 0
X
01) ............................................................................................ 26
2.4.4 The Transmit Line Build-Out Circuit and E3 Applications .................................................. 26
2.5 I
NTERFACING
THE
T
RANSMIT
S
ECTION
OF
THE
XRT73L00
TO
THE
L
INE
................................................ 26
Figure 15. Recommended Schematic for Interfacing the Transmit Section of the XRT73L00 to the Line ...... 26
T
RANSFORMER
R
ECOMMENDATIONS
............................................................................................... 27
3.0 The Receive Section ................................................................................................. 27
3.1 I
NTERFACING
THE
R
ECEIVE
S
ECTION
OF
THE
XRT73L00
TO
THE
L
INE
................................................... 28
Figure 16. Recommended Schematic for Interfacing the Receive Section of the XRT73L00 to the Line (Trans-
former-Coupling) ........................................................................................................................... 28
Figure 17. Recommended Schematic for Interfacing the Receive Section of the XRT73L00 to the Line (Capac-
itive-Coupling) ............................................................................................................................... 28
3.2 T
HE
R
ECEIVE
E
QUALIZER
B
LOCK
......................................................................................................... 28
3.2.1 Guidelines for Setting the Receive Equalizer ....................................................................... 29
Figure 18. The Typical Application for the System Installer ........................................................................... 30
3.3 P
EAK
D
ETECTOR
AND
S
LICER
............................................................................................................... 31
3.4 C
LOCK
R
ECOVERY
PLL ....................................................................................................................... 31
C
OMMAND
R
EGISTER
CR2 (A
DDRESS
= 0
X
02) ............................................................................................ 31
3.5 T
HE
HDB3/B3ZS D
ECODER
................................................................................................................ 31
3.5.1 B3ZS Decoding DS3/STS-1 Applications .............................................................................. 31
Figure 19. An Example of B3ZS Decoding ..................................................................................................... 32
3.5.2 HDB3 Decoding E3 Applications ........................................................................................... 32
Figure 20. An Example of HDB3 Decoding ..................................................................................................... 32
3.5.3 Enabling/Disabling the HDB3/B3ZS Decoder ....................................................................... 32
3.6 LOS D
ECLARATION
/C
LEARANCE
.......................................................................................................... 33
C
OMMAND
R
EGISTER
CR2 (A
DDRESS
= 0
X
02) ............................................................................................ 33
3.6.1 The LOS Declaration/Clearance Criteria for E3 Applications ............................................. 33
Figure 21. The Signal Levels that the XRT73L00 Declares and Clears LOS (E3 Mode Only) ....................... 33
Figure 22. The Behavior the LOS Output Indicator In Response to the Loss of Signal and the Restoration of
Signal ............................................................................................................................................ 34
3.6.2 The LOS Declaration/Clearance Criteria for DS3 and STS-1 Applications ........................ 34
T
ABLE
4: T
HE
ALOS D
ECLARATION
AND
C
LEARANCE
T
HRESHOLDS
FOR
A
G
IVEN
S
ETTING
OF
LOSTHR (DS3
AND
STS-1 A
PPLICATIONS
)
FOR
E
QUALIZER
E
NABLED
OR
D
ISABLED
........................................................... 35
C
OMMAND
R
EGISTER
CR0 (A
DDRESS
= 0
X
00) ............................................................................................ 35
C
OMMAND
R
EGISTER
CR2 (A
DDRESS
= 0
X
02) ............................................................................................ 35
3.6.3 Muting the Recovered Data while the LOS is being Declared ............................................ 36
C
OMMAND
R
EGISTER
CR0 (A
DDRESS
= 0
X
00) ............................................................................................ 36
C
OMMAND
R
EGISTER
CR2 (A
DDRESS
= 0
X
02) ............................................................................................ 36
3.7 R
OUTING
THE
R
ECOVERED
T
IMING
AND
D
ATA
I
NFORMATION
TO
THE
R
ECEIVING
T
ERMINAL
E
QUIPMENT
.. 36
C
OMMAND
R
EGISTER
CR3 (A
DDRESS
= 0
X
03) ............................................................................................ 36
Figure 23. The Typical Interface for the Transmission of Data in a Dual-Rail Format From the Receive Section
of the XRT73L00 to the Receiving Terminal Equipment ............................................................... 37
Figure 24. How the XRT73L00 Outputs Data on the RPOS and RNEG Output Pins .................................... 37
Figure 25. The Behavior of the RPOS, RNEG and RCLK1 Signals When RCLK1 is Inverted ....................... 38
3.7.1 Routing Single-Rail Format data (Binary Data Stream) to the Receive Terminal Equipment
38
C
OMMAND
R
EGISTER
CR3 (A
DDRESS
= 0
X
03) ............................................................................................ 38
C
OMMAND
R
EGISTER
CR3 (A
DDRESS
= 0
X
03) ............................................................................................ 38
Figure 26. The Typical Interface for the Transmission of Data in a Single-Rail Format From the Receive Section
of the XRT73L00 to the Receiving Terminal Equipment ............................................................... 38
Figure 27. The Behavior of the RPOS and RCLK1 Output Signals While the XRT73L00 is Transmitting Single-
Rail Data to the Receiving Terminal Equipment ........................................................................... 39
4.0 Diagnostic Features of the XRT73L00 ..................................................................... 39
4.1 T
HE
A
NALOG
L
OCAL
L
OOP
-B
ACK
M
ODE
.............................................................................................. 39