ZHCSCX2E January 2014 – October 2017 LM15851
PRODUCTION DATA.
The PRBS test modes bypass the 8B10B encoder. These test modes produce pseudo-random bit streams that comply with the ITU-T O.150 specification. These bit streams are used with lab test equipment that can self-synchronize to the bit pattern and therefore the initial phase of the pattern is not defined.
The sequences are defined by a recursive equation. For example, the PRBS7 sequence is defined as shown in Equation 9.
where
PRBS TEST MODE | SEQUENCE | SEQUENCE LENGTH (bits) |
---|---|---|
PRBS7 | y[n] = y[n – 6]y[n – 7] | 127 |
PRBS15 | y[n] = y[n – 14]y[n – 15] | 32767 |
PRBS23 | y[n] = y[n – 18]y[n – 23] | 8388607 |
The initial phase of the pattern is unique for each lane.