STANDARD PRODUCT
PM4328 TECT3
DATASHEET
PMC-2011596
ISSUE 1
HIGH DENSITY T1/E1 FRAMER
AND M13 MULTIPLEXER
The PRGD can be programmed to generate any pseudo-random pattern with
length up to 232-1 bits or any user programmable bit pattern from 1 to 32 bits in
length. In addition, the PRGD can insert single bit errors or a bit error rate
-1
-7
between 10 to 10 .
The PRGD can be programmed to check for the generated pseudo random
pattern. The PRGD can perform an auto synchronization to the expected pattern
and accumulates the total number of bits received and the total number of bit
errors in two 32-bit counters. The counters accumulate either over intervals
defined by writes to the Pattern Detector registers, upon writes to the Global
PMON Update Register or automatically once a second. When an accumulation
is forced, the holding registers are updated, and the counters reset to begin
accumulating for the next interval. The counters are reset in such a way that no
events are missed. The data is then available in the holding registers until the
next accumulation.
9.22 DS3 Framer (DS3-FRMR)
The DS3 Framer (DS3-FRMR) Block integrates circuitry required for decoding a
B3ZS-encoded signal and framing to the resulting DS3 bit stream. The
DS3-FRMR is directly compatible with the M23 and C-bit parity DS3 applications.
The DS3-FRMR decodes a B3ZS-encoded signal and provides indications of line
code violations. The B3ZS decoding algorithm and the LCV definition can be
independently chosen through software. A loss of signal (LOS) defect is also
detected for B3ZS encoded streams. LOS is declared when inputs RPOS and
RNEG contain zeros for 175 consecutive RCLK cycles. LOS is removed when
the ones density on RPOS and/or RNEG is greater than 33% for 175 ±1 RCLK
cycles.
The framing algorithm examines five F-bit candidates simultaneously. When at
least one discrepancy has occurred in each candidate, the algorithm examines
the next set of five candidates. When a single F-bit candidate remains in a set,
the first bit in the supposed M-subframe is examined for the M-frame alignment
signal (i.e., the M-bits, M1, M2, and M3 are following the 010 pattern). Framing
is declared, and out-of-frame is removed, if the M-bits are correct for three
consecutive M-frames while no discrepancies have occurred in the F-bits.
During the examination of the M-bits, the X-bits and P-bits are ignored. The
algorithm gives a maximum average reframe time of 1.5 ms.
While the DS3-FRMR is synchronized to the DS3 M-frame, the F-bit and M-bit
positions in the DS3 stream are examined. An out-of-frame defect is detected
when 3 F-bit errors out of 8 or 16 consecutive F-bits are observed (as selected
by the M3O8 bit in the DS3 FRMR Configuration Register), or when one or more
PROPRIETARY AND CONFIDENTIAL
78
PMC [ PMC-SIERRA, INC ]
