Preliminary Data Sheet
May 2001
TMXF28155/51 Super Mapper
155/51 Mbits/s SONET/SDH x28/x21 DS1/E1
417
Agere Systems Inc.
18 SPE Mapper Functional Description
(continued)
Table 545. Signal Degrade Parameters
Note: The threshold written by the control system is one less than the desired number, except for the SPE_SDLSET[3:0]/SDLCLEAR[3:0]
parameter.
18.14.12 Signal Fail BER Algorithm
A signal fail state is reported by bit SPE_SFB3 (
Table 148 on pag e137
) and change of state in bit SPE_SFB3D
(
Table 146
) with the interrupt mask bit SPE_SFB3M (
Table 147
). This bit error rate algorithm operates on B3 errors.
Declaring the signal fail state requires the definition of two measurement windows, a monitoring block consisting of
a number of frames, Ns (SPE_SFNSSET[18:0] (
Table 159 on page146
)), and a measurement interval consisting
of a number of monitoring blocks, B (SPE_SFBSET[15:0] (
Table 159
)). A block is determined to be bad when the
number of bit errors equals or exceeds a threshold, L (SPE_SFLSET[3:0] (v)). Signal fail is declared when the
number of bad monitoring blocks equals or exceeds the threshold, M (SPE_SFMSET[7:0] (
Table 159
)), for the
measurement interval.
Clearing the signal fail state requires the definition of two measurement windows, a monitoring block consisting of a
number of frames, Ns (SPE_SFNSCLEAR[18:0] (
Table 159
)), and a measurement interval consisting of a number
of monitoring blocks, B (SPE_SFBCLEAR[11:0] (v)). A block is determined to be good when the number of bit
errors is less than a threshold, L (SPE_SFLCLEAR[3:0] (
Table 159
)). Signal fail is cleared when a number of good
monitoring blocks equals or exceeds the threshold, M (SPE_SFMCLEAR[7:0] (v)), for the measurement interval.
The set parameters are used when the signal fail state is clear, and the clear parameters are used when the signal
fail state is declared.
The signal fail state may be forced to the declared state with bit SPE_SFSET (
Table 145 on page134
) and forced
to the cleared state with bit SPE_SFCLEAR (
Table 145
).
The above algorithm can detect bit error rates from 1 x 10
–
3
to 1 x 10
–
9
.
Name
Function
SPE_SDNSSET[18:0] (
Table 158
)
SPE_SDLSET[3:0] (
Table 158
)
Signal Degrade Ns Set.
Number of frames in a monitoring block for SD.
Signal Degrade L Set.
Error threshold for determining if a monitoring
block is bad.
Signal Degrade M Set.
Threshold of the number of bad monitoring blocks
in an observation interval. If the number of bad blocks is below this thresh-
old, then SD is cleared.
Signal Degrade B Set.
Number of monitoring blocks in a measurement
interval.
SPE_SDMSET[7:0] (
Table 158
)
SPE_SDBSET[15:0] (
Table 158
)
SPE_SDNSCLEAR[18:0] (
Table 158
)
Signal Degrade Ns Clear.
Number of frames in a monitoring block for SD.
SPE_SDLCLEAR[3:0] (
Table 158
)
Signal Degrade L Clear.
Error threshold for determining if a monitoring
block is bad.
SPE_SDMCLEAR[7:0] (
Table 158
)
Signal Degrade M Clear.
Threshold of the number of bad monitoring
blocks in an observation interval. If the number of bad blocks is below this
threshold, then SD is cleared.
SPE_SDBCLEAR[15:0] (
Table 158
)
Signal Degrade B Clear.
Number of monitoring blocks in a measurement
interval.
SPE_SDSET (
Table 145
)
Signal Degrade Set.
Allows the signal degrade algorithm to be forced into
the failed state (active 0 to 1).
SPE_SDCLEAR (
Table 145
)
Signal Degrade Clear.
Allows the signal degrade algorithm to be forced
into the normal state (active 0 to 1).
SPE_SDB3 (
Table 148
)
Signal Degrade BER Algorithm State Bit.
SPE_SDB3D (
Table 146
)
Signal Degrade BER Algorithm Delta Bit.
SPE_SDB3M (
Table 147
)
Signal Degrade BER Algorithm Mask Bit.