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XRT7300
E3/DS3/STS-1 LINE INTERFACE UNIT
REV. 1.1.1
NOTE: If the B3ZS Decoder detects any bipolar violations
that is not in accordance with the”B3ZS Line Code” format,
or if the B3ZS Decoder detects a string of 3 (or more) con-
secutive “0’s” in the incoming line signal, then the B3ZS
Decoder flags this event as a Line Code Violation by puls-
ing the LCV output pin “High”.
ted over the E3, DS3 or STS-1 line) to its original con-
tent prior to Zero Suppression encoding.
3.5.1 B3ZS Decoding DS3/STS-1 Applications
If the XRT7300 is configured to operate in the DS3 or
STS-1 Modes, then the HDB3/B3ZS Decoding Block
performs B3ZS Decoding. When the Decoder is op-
erating in this mode it parses through the incoming
Dual-Rail data and checks for the occurrence of ei-
ther a “00V” or a “B0V” pattern. If the B3ZS Decoder
detects this particular pattern it substitutes these bits
with a “000” pattern.
Figure 19 illustrates the B3ZS Decoder at work with
two separate Zero Suppression patterns in the in-
coming Dual-Rail Data Stream.
FIGURE 19. AN EXAMPLE OF B3ZS DECODING
0 0
V
Line Signal
RCLK
B
0 V
RPOS
RNEG
Data
0
1
0
1
1
0
0
0
1
0
1
1
1
1
0
1
1
0
1
1
0
0
1
1
1
0 0 0 1
3.5.2 HDB3 Decoding E3 Applications
or a “B00V” pattern. If the HDB3 Decoder detects
this particular pattern, it substitutes these bits with a
“0000” pattern.
If the XRT7300 is configured to operate in the E3
Mode, the HDB3/B3ZS Decoding Block performs
HDB3 Decoding. When the Decoder is operating in
this mode it parses through the incoming Dual-Rail
Figure 20 illustrates the HDB3 Decoder at work with
two separate Zero Suppression patterns in the in-
coming Dual-Rail Data Stream.
data and checks for the occurrence of either a “000V”
FIGURE 20. AN EXAMPLE OF HDB3 DECODING
0 0
0 V
Line Signal
RCLK
B
0 0 V
RPOS
RNEG
Data
0
1 0 1 1 0 0 0 0 0 1 1 1 1 0 1 1 0 1 1 0 0 1 1 0 0 0 0 1
NOTE: If the HDB3 Decoder detects any bipolar violation
(e.g., “V”) pulses that is not in accordance with the HDB3
Line Code format, or if the HDB3 Decoder detects a string
of 4 (or more) “0’s” in the incoming line signal, then the
HDB3 Decoder flags this event as a Line Code Violation by
pulsing the LCV output pin “High”.
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