ZHCSHO8A February 2018 – April 2020 ADC08DJ3200
PRODUCTION DATA.
The PRBS test modes bypass the 8b, 10b 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, Equation 3 defines the PRBS7 sequence.
where
Table 18 lists equations and sequence lengths for the available PRBS test modes. The initial phase of the pattern is unique for each lane.
| 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 |