STANDARD PRODUCT
PM5365 TEMAP
DATASHEET
PMC-1991148
ISSUE 3
HIGH DENSITY VT/TU MAPPER
AND M13 MULTIPLEXER
gap + 207 clocks + 1 clock gap + 207 clocks + 1 clock gap is used. To generate
622 pulses, a gap pattern of 207 clocks + 1 clock gap + 207 clocks + 1 clock gap
+ 208 clocks is used.
When using a 51.84 MHz CLK52M clock, the DS3 clock is generated using
similar gapping patterns. To generate 621 pulses per row, a gapping pattern of
63 * (7 clocks + 1 clock gap) + 36 * (5 clocks + 1 clock gap) is used. To generate
622 pulses per row, a gapping pattern of 63 * (7 clocks + 1 clock gap) + 35 * (5
clocks + 1 clock gap) + 6 clocks is used.
Table 8 illustrates the gap patterns used to generate the desynchronized DS3
clock under the normal, DS3 AIS, faster and slower status. The faster pattern is
used to drain the elastic store to avoid overflows. The slower pattern is used to
allow the elastic store to fill to avoid underflows.
Table 8
- DS3 desynchronizer clock gapping algorithm.
Row Number
Normal or DS3 AIS
Run Faster
Run Slower
1
2
3
4
5
6
7
8
9
621
621
622
621
621
622
621
621
622
621
621
622
621
622
622
621
622
622
621
621
622
621
621
621
621
621
621
9.20 Transmit Tributary Path Overhead Processor (TTOP)
The Transmit Tributary Path Overhead Processor (TTOP) generates the path
overhead for up to 28 VT1.5/TU-11s or 21 VT2/TU-12s.
When configured for SONET compatible operation, the TTOP inserts the four
tributary path overhead bytes (V5, J2, Z6, and Z7) to each tributary. The TTOP
may also be configured for SDH compatible operation. The incoming STM-1
stream may carry three AU3s or an AU4 with three TUG3s.
The TTOP computes the BIP-2 code in the current tributary SPE and inserts the
result into the BIP-2 bits of the V5 byte in the next tributary SPE. The tributary
Proprietary and Confidential to PMC-Sierra, Inc. and for its Customers’ Internal Use
92
PMC [ PMC-SIERRA, INC ]
