XRT73L03 Datasheet, PDF (40/62 Pages) Exar Corporation – 3 CHANNEL E3/DS3/STS-1 LINE INTERFCE UNIT

XRT73L03 3 CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT
REV. P1.0.13
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PRELIMINARY
flags this event as a Line Code Violation by pulsing the LCV
output pin “High".
Figure 20 illustrates the B3ZS Decoder at work with
two separate Zero Suppression patterns in the in-
coming Dual-Rail Data Stream.
FIGURE 20. AN EXAMPLE OF B3ZS DECODING
Line Signal
00 V
RxClk
B 0V
RPOS
RNEG
Data
01011000101111011011001110001
3.4.2 HDB3 Decoding E3 Applications
If the XRT73L03 is configured to operate in the E3
Mode, then each of the HDB3/B3ZS Decoding Blocks
performs HDB3 Decoding. When the Decoders are
operating in this mode, they each parse through the
incoming Dual-Rail data and check for the occurrence
FIGURE 21. AN EXAMPLE OF HDB3 DECODING
of either a "000V" or a "B00V" pattern. If the HDB3
Decoder detects this particular pattern, it substitutes
these bits with a "0000" pattern.
Figure 21 illustrates the HDB3 Decoder at work with
two separate Zero Suppression patterns in the in-
coming Dual-Rail Data Stream.
Line Signal
000 V
RxClk
B 0 0V
RPOS
RNEG
Data
01011000001111011011001100001
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, the HDB3
Decoder flags this event as a Line Code Violation by puls-
ing the LCV output pin “High".
3.4.3 Configuring the HDB3/B3ZS Decoder
The XRT73L03 can enable or disable the HDB3/
B3ZS Decoder blocks of each Channel by either of
the following means.
a. Operating in the HOST Mode
Enable the HDB3/B3ZS Decoder block of Channel(n)
by writing a "0" into the ENDECDIS(n) bit-field in
Command Register CR2-(n).
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