ZHCSN42B August 2021 – April 2025 ADC08DJ5200RF
PRODUCTION DATA
The PRBS test modes bypass the JESD204C transport layer and link layer and are therefore neither scrambled nor encoded. 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 or logic devices that can self-synchronize to the bit pattern. The initial phase of the pattern is not defined since the receiver self synchronizes.
The sequences are defined by a recursive equation. For example, Equation 8 defines the PRBS7 sequence.
where
Table 6-25 lists equations and sequence lengths for the available PRBS test modes where ⊕ is the XOR operation and y[n] represents bit n in the PRBS sequence. 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 |
| PRBS9 | y[n] = y[n – 5]⊕y[n – 9] | 511 |
| PRBS15 | y[n] = y[n – 14]⊕y[n – 15] | 32,767 |
| PRBS23 | y[n] = y[n – 18]⊕y[n – 23] | 8,388,607 |
| PRBS31 | y[n] = y[n – 28]⊕y[n – 31] | 2,147,483,647 |