XRT72L13 Datasheet, PDF (301/370 Pages) Exar Corporation – M13 MULTIPLEXER/CLEAR CHANNEL DS3 FRAMER IC

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PRELIMINARY
XRT72L13
M13 MULTIPLEXER/CLEAR CHANNEL DS3 FRAMER IC
REV. P1.0.6
FIGURE 94. ILLUSTRATION ON HOW THE RECEIVE DS3 FRAMER (WITHIN THE XRT72L13 FRAMER IC) BEING INTER-
FACE TO THEXRT7300 LINE INTERFACE UNIT, WHILE THE FRAMER IS OPERATING IN BIPOLAR MODE
TxSER
TxInClk
TxFrame
NIBBLEINTF
RESETB
INTB
CSB
RW
DS
AS
INTB
A[8:0]
D[7:0]
5V
RxSer
RxClk
RxFrame
RxLOS
RxOOF
RxRED
RxAIS
U1
46
43 ^TxSER
61
TxInClk
TxFrame
25
NIBBLEINTF
28
RESETB
13
8 ^INTB
7 ^CSB
10 ^WRB_RW
9 ^RDB_DS
6
ALE_AS
Rdy_Dtck
15
16 ^A0
17 ^A1
18 ^A2
19 ^A3
20 ^A4
21 ^A5
22 ^A6
23
A7
A8
32
33 ^D0
34 ^D1
35 ^D2
36 ^D3
37 ^D4
38
39
D5
D6
D7
27
MOTO
86
88 ^RxSer
90 ^RxClk
RxFrame
95
94
93
RxLOS
RxOOF
87 ^RxRED
RxAIS
XRT72L13
65
TxPOS
64
TxNEG
63
TxLineClk
79
DMO
78
ExtLOS
RLOL ⁷⁷
69
LLOOP
70
RLOOP
68
TAOS
67
TxLEV
66
ENCODIS
71
REQB
76
RxPOS
75
RxNEG
74
RxLineClk
U2
37
TPDATA
38
TNDATA
36
TCLK
4
DMO
24
RLOS
23 _RLOL
14
LLB
15
RLB
2
TAOS
1
TxLEV
21
ENCODIS
12
REQDIS
33
RPOS
32
RNEG
31
RCLK1
XRT7300
41
TTIP
40
TRING
44
MTIP
43
MRING
1 ^R3 2
270
1 ^R4 2
270
R1
1
2
36
1 ^T1 5
R2
1
2
36
4
8
1:1
TTIP
TRING
8
RTIP
9
RRING
C1
12
0.01uF
R5
37.5
R6
37.5
1 ^T2 5
4
8
1:1
RTIP
RRING
4.3.1.2.1 AMI Decoding
AMI or Alternate Mark Inversion, means that consec-
utive "one's" pulses (or marks) will be of opposite po-
larity with respect to each other. This line code in-
volves the use of three different amplitude levels: +1,
0, and -1. The +1 and -1 amplitude signals are used
to represent one's (or mark) pulses and the "0" ampli-
tude pulses (or the absence of a pulse) are used to
represent zeros (or space) pulses. The general rule
for the AMI line code is: if a given "mark" pulse is of
FIGURE 95. ILLUSTRATION OF AMI LINE CODE
positive polarity, then the very next "mark" pulse will
be of negative polarity and vice versa. This alternat-
ing-polarity relationship exists between two consecu-
tive mark pulses, independent of the number of zeros
that exist between these two pulses. Figure 95 pre-
sents an illustration of the AMI Line Code as would
appear at the “RxPOS” and “RxNEG” input pins of the
Framer, as well as the corresponding output signal on
the line.
Data 1 0 1 1 0 0 0 1 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 0 0 0 0 1
Line Signal
RxPOS
RxNEG
NOTE: One of the reasons that the AMI Line Code has
formers, is that this line code has no dc component; thereby
been chosen for driving copper medium, isolated via trans- eliminating dc distortion in the line.
289