PM7346 S/UNI-QJET
DATASHEET
PMC-960835
ISSUE 6
SATURN QUAD USER NETWORK INTERFACE FOR J2, E3, T3
Figure 8
- Framing algorithm (CRC_REFR = 0)
Reset
or
Out of Fram e
Else
Slip 1 bit
Framing
Pattern
Matched
Mark multiframe alignment
Fail
Fail
Confirm Framing Pattern
in next multiframe
Pass
Confirm Framing Pattern
in next m ultiframe
Pass
Declare in-frame
Using this algorithm, the J2-FRMR will on average find frame in 5.07ms when
starting the search in the worst possible position, given a 10-4 error rate and no
static mimic patterns.
When the CRC_REFR bit is set to logic 1, in addition to requiring three
consecutive correct framing patterns, the J2-FRMR requires that the first two
CRC-5 checks be correct, or a reframe is initiated. To speed the process, the
CRC-5 and frame alignment checks are run concurrently, as illustrated in Figure
9.
PMC-SIERRA, INC. PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA INC., AND ITS CUSTOMERS’ INTERNAL USE 63
PMC [ PMC-SIERRA, INC ]
