PM5343STXC View Datasheet(PDF) - PMC-Sierra
Part Name
Description
MFG CO.
'PM5343STXC' PDF : 198 Pages View PDF
DATA SHEET
PMC-930303
ISSUE 6
PM5343 STXC
SONET/SDH TRANSPORT OVERHEAD TRANSCEIVER
parallel converter) that searches for occurrences of the framing pattern (A1, A2)
in the bit serial data stream. Once the external serial to parallel converter has
found byte-alignment, the RSOP block monitors for the next occurrence of the
framing pattern 125µs later. The block declares frame alignment when either all
A1 and A2 bytes are seen error-free or when only the first A1 byte and the first
four bits of the A2 byte are seen error-free. Depending upon the operating mode,
the first algorithm examines 2 bytes (A1,A2) in STS-1 mode, or 6 bytes
(A1A1A1,A2A2A2) in STS-3/STM-1 mode. The second algorithm examines only
the first occurrence of A1 and the first four bits of the first occurrence of A2 in the
sequence, regardless of the operating mode. Once in frame, the RSOP block
monitors the framing pattern sequence and declares OOF when one or more bit
errors in each framing pattern are detected for four consecutive frames. Again,
depending upon the operating mode selected the first algorithm examines all 2,
or 6 framing bytes for bit errors each frame, while the second algorithm examines
only the A1 byte and the first four bits of the A2 byte (i.e. 12 bits total) during
each frame.
The performance of these framing algorithms in the presence of bit errors and
random data is robust. When looking for frame alignment the performance of
each algorithm is dominated by the alignment algorithm used in the serial to
parallel converter. Assuming that the SIPO block is used, the probability of
falsely framing to random data is less than 0.00001% for either algorithm. Once
in frame alignment, the STXC continuously monitors the framing pattern. When
the incoming stream contains a 10-3 BER, the first algorithm provides a mean
time between OOF occurrences of 33 minutes in STS-1 mode and 26 seconds in
STS-3/STM-1 mode. The second algorithm provides a mean time between OOF
occurrences of 103 minutes, regardless of operating mode.
The RSOP block provides descrambled data and frame alignment indication
signals for use by the Receive Line Overhead Processor.
9.3 Receive Line Overhead Processor
The Receive Line Overhead Processor block (RLOP) processes the line
overhead (multiplexer section) of a received SONET/SDH data stream. It can be
configured to process an STS-1, or an STS-3/STM-1 stream.
The SONET frame alignment is indicated by the Receive Section Overhead
Processor. The RLOP extracts the line data communication channel, line order
wire channel and automatic protection switch channel from the line overhead,
and provides them as lower rate bit serial outputs (RLD, RLOW, RAPS) together
with associated clock signals (RLDCLK, ROWCLK, RAPSCLK). Line alarm
indication signal is declared (LAIS is set high) when the bit pattern 111 is
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA INC., AND FOR ITS CUSTOMERS’ INTERNAL USE 37
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